Merge branch 'master' into bitwise-operators

.dependabot/config.yml

-version: 1
-update_configs:
-  - package_manager: "python"
-    directory: "/requirements.txt"
-    update_schedule: "monthly"

.github/ISSUE_TEMPLATE/bug_report.md

+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+:information_source: Please note that the best way to get support for Real Python courses & articles is to join one of our [weekly Office Hours calls](https://realpython.com/office-hours/) or in the [RP Community Slack](https://realpython.com/community/). 
+
+You can report issues and problems here, but we typically won't be able to provide 1:1 support outside the channels listed above.
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+Steps to reproduce the behavior:
+1. Go to '...'
+2. Click on '....'
+3. Scroll down to '....'
+4. See error
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem.
+
+**Desktop (please complete the following information):**
+ - OS: [e.g. iOS]
+ - Browser [e.g. chrome, safari]
+ - Version [e.g. 22]
+
+**Smartphone (please complete the following information):**
+ - Device: [e.g. iPhone6]
+ - OS: [e.g. iOS8.1]
+ - Browser [e.g. stock browser, safari]
+ - Version [e.g. 22]
+
+**Additional context**
+Add any other context about the problem here.

.github/dependabot.yml

+version: 2
+updates:
+- package-ecosystem: pip
+  directory: "/"
+  schedule:
+    interval: monthly
+  open-pull-requests-limit: 10
+  allow:
+  - dependency-name: flake8
+  - dependency-name: black

.gitignore

@@ -108,3 +108,6 @@ ENV/
 
 # Mac
 *.DS_Store
+
+# VS Code workspace
+*.code-workspace
\ No newline at end of file

README.md

 # Real Python Materials
 
-Bonus materials, exercises, and example projects for our [Python tutorials](https://realpython.com).
+Bonus materials, exercises, and example projects for Real Python's [Python tutorials](https://realpython.com).
 
 Build Status: [![CircleCI](https://circleci.com/gh/realpython/materials.svg?style=svg)](https://circleci.com/gh/realpython/materials)
 
-## Running Code Style Checks
+## Got a Question?
+
+The best way to get support for Real Python courses & articles and code in this repository is to join one of our [weekly Office Hours calls](https://realpython.com/office-hours/) or to ask your question in the [RP Community Slack](https://realpython.com/community/). 
+
+Due to time constraints we cannot provide 1:1 support via GitHub. See you on Slack or on the next Office Hours call 🙂
+
+## Adding Source Code & Sample Projects to This Repo (RP Contributors)
+
+### Running Code Style Checks
 
 We use [flake8](http://flake8.pycqa.org/en/latest/) and [black](https://github.com/ambv/black) to ensure a consistent code style for all of our sample code in this repository.
 
@@ -15,7 +23,7 @@ $ flake8
 $ black --check .
 ```
 
-## Running Python Code Formatter
+### Running Python Code Formatter
 
 We're using a tool called [black](https://github.com/ambv/black) on this repo to ensure consistent formatting. On CI it runs in "check" mode to ensure any new files added to the repo are following PEP 8. If you see linter warnings that say something like "would reformat some_file.py" it means black disagrees with your formatting. 
 

arcade-a-primer/arcade_basic_oop.py

@@ -14,12 +14,10 @@ RADIUS = 150
 
 
 class Welcome(arcade.Window):
-    """Our main welcome window
-    """
+    """Our main welcome window"""
 
     def __init__(self):
-        """Initialize the window
-        """
+        """Initialize the window"""
 
         # Call the parent class constructor
         super().__init__(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
@@ -28,8 +26,7 @@ class Welcome(arcade.Window):
         arcade.set_background_color(arcade.color.WHITE)
 
     def on_draw(self):
-        """Called whenever we need to draw our window
-        """
+        """Called whenever we need to draw our window"""
 
         # Clear the screen and start drawing
         arcade.start_render()

arcade-a-primer/arcade_draw_shapes.py

@@ -13,12 +13,10 @@ SCREEN_TITLE = "Draw Shapes"
 
 
 class Welcome(arcade.Window):
-    """Our main welcome window
-    """
+    """Our main welcome window"""
 
     def __init__(self):
-        """Initialize the window
-        """
+        """Initialize the window"""
 
         # Call the parent class constructor
         super().__init__(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
@@ -27,8 +25,7 @@ class Welcome(arcade.Window):
         arcade.set_background_color(arcade.color.WHITE)
 
     def on_draw(self):
-        """Called whenever we need to draw our window
-        """
+        """Called whenever we need to draw our window"""
 
         # Clear the screen and start drawing
         arcade.start_render()

arcade-a-primer/arcade_game.py

@@ -41,8 +41,7 @@ class SpaceShooter(arcade.Window):
     """
 
     def __init__(self, width: int, height: int, title: str):
-        """Initialize the game
-        """
+        """Initialize the game"""
         super().__init__(width, height, title)
 
         # Setup the empty sprite lists
@@ -51,8 +50,7 @@ class SpaceShooter(arcade.Window):
         self.all_sprites = arcade.SpriteList()
 
     def setup(self):
-        """Get the game ready to play
-        """
+        """Get the game ready to play"""
 
         # Set the background color
         arcade.set_background_color(arcade.color.SKY_BLUE)
@@ -236,8 +234,7 @@ class SpaceShooter(arcade.Window):
             self.player.left = 0
 
     def on_draw(self):
-        """Draw all game objects
-        """
+        """Draw all game objects"""
 
         arcade.start_render()
         self.all_sprites.draw()

concurrency-overview/requirements.txt

@@ -8,7 +8,6 @@ attrs==18.1.0
 certifi==2018.8.13
 chardet==3.0.4
 contextvars==2.3
-flake8==3.5.0
 h11==0.8.1
 idna==2.7
 immutables==0.6
@@ -23,8 +22,6 @@ pathlib2==2.3.2
 pluggy==0.7.1
 py==1.6.0
 pycodestyle==2.3.1
-pyflakes==1.6.0
-pylint==2.1.1
 pytest==3.7.3
 requests==2.19.1
 six==1.11.0

django-view-auth/.gitignore

+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~
+.DS_Store
+*.pyc
+*.o
+*.so
+*.swp
+*~
+.coverage*
+htmlcov/
+foo.py
+debug.log
+db.sqlite3
+logs/*
+*.egg
+*.eggs
+*.egg-info
+build/
+dist/
+docs/_build/
+extras/sample_site/uploads/
+extras/sample_site/db.sqlite3
+.tox/

django-view-auth/Blog/Blog/asgi.py

+"""
+ASGI config for Blog project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/3.0/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "Blog.settings")
+
+application = get_asgi_application()

django-view-auth/Blog/Blog/settings.py

+"""
+Django settings for Blog project.
+
+Generated by 'django-admin startproject' using Django 3.0.7.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/3.0/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/3.0/ref/settings/
+"""
+
+import os
+
+# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
+BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/3.0/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = "9p2cpl%!f8a0tptz_85&dulu&!_ve=j_0s6-l4=tc-g!p-$whj"
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+# Application definition
+
+INSTALLED_APPS = [
+    "django.contrib.admin",
+    "django.contrib.auth",
+    "django.contrib.contenttypes",
+    "django.contrib.sessions",
+    "django.contrib.messages",
+    "django.contrib.staticfiles",
+    "core",
+]
+
+MIDDLEWARE = [
+    "django.middleware.security.SecurityMiddleware",
+    "django.contrib.sessions.middleware.SessionMiddleware",
+    "django.middleware.common.CommonMiddleware",
+    "django.middleware.csrf.CsrfViewMiddleware",
+    "django.contrib.auth.middleware.AuthenticationMiddleware",
+    "django.contrib.messages.middleware.MessageMiddleware",
+    "django.middleware.clickjacking.XFrameOptionsMiddleware",
+]
+
+ROOT_URLCONF = "Blog.urls"
+
+TEMPLATES = [
+    {
+        "BACKEND": "django.template.backends.django.DjangoTemplates",
+        "DIRS": [os.path.join(BASE_DIR, "templates")],
+        "APP_DIRS": True,
+        "OPTIONS": {
+            "context_processors": [
+                "django.template.context_processors.debug",
+                "django.template.context_processors.request",
+                "django.contrib.auth.context_processors.auth",
+                "django.contrib.messages.context_processors.messages",
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = "Blog.wsgi.application"
+
+
+# Database
+# https://docs.djangoproject.com/en/3.0/ref/settings/#databases
+
+DATABASES = {
+    "default": {
+        "ENGINE": "django.db.backends.sqlite3",
+        "NAME": os.path.join(BASE_DIR, "db.sqlite3"),
+    }
+}
+
+
+# Password validation
+# https://docs.djangoproject.com/en/3.0/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = []
+
+
+# Internationalization
+# https://docs.djangoproject.com/en/3.0/topics/i18n/
+
+LANGUAGE_CODE = "en-us"
+
+TIME_ZONE = "UTC"
+
+USE_I18N = True
+
+USE_L10N = True
+
+USE_TZ = True
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/3.0/howto/static-files/
+
+STATIC_URL = "/static/"

django-view-auth/Blog/Blog/urls.py

+from django.contrib import admin
+from django.urls import path, include
+from core import views as core_views
+
+urlpatterns = [
+    path("admin/", admin.site.urls),
+    path("", core_views.listing, name="listing"),
+    path("view_blog/<int:blog_id>/", core_views.view_blog, name="view_blog"),
+    path("see_request/", core_views.see_request),
+    path("user_info/", core_views.user_info),
+    path("private_place/", core_views.private_place),
+    path("accounts/", include("django.contrib.auth.urls")),
+    path("staff_place/", core_views.staff_place),
+    path("add_messages/", core_views.add_messages),
+]

django-view-auth/Blog/Blog/wsgi.py

+"""
+WSGI config for Blog project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/3.0/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "Blog.settings")
+
+application = get_wsgi_application()

django-view-auth/Blog/core/admin.py

+from django.contrib import admin
+from core.models import Blog
+
+
+@admin.register(Blog)
+class BlogAdmin(admin.ModelAdmin):
+    pass

django-view-auth/Blog/core/apps.py

+from django.apps import AppConfig
+
+
+class CoreConfig(AppConfig):
+    name = "core"

django-view-auth/Blog/core/fixtures/core.json

+[{"model": "core.blog", "pk": 1, "fields": {"title": "Fruit", "content": "<p> Turns out, you can compare them: </p>\r\n\r\n<ul>\r\n   <li>Apple</li>\r\n   <li>Orange</li>\r\n</ul>"}}, {"model": "core.blog", "pk": 2, "fields": {"title": "I like airplanes", "content": "I prefer them to be very <i>fast</i>. I wish the Concorde still existed."}}]
\ No newline at end of file

django-view-auth/Blog/core/migrations/0001_initial.py

+# Generated by Django 3.0.7 on 2020-07-31 15:14
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name="Blog",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("title", models.CharField(max_length=50)),
+                ("content", models.TextField()),
+            ],
+        ),
+    ]

django-view-auth/Blog/core/models.py

+from django.db import models
+
+
+class Blog(models.Model):
+    title = models.CharField(max_length=50)
+    content = models.TextField()

django-view-auth/Blog/core/views.py

+from django.contrib import messages
+from django.contrib.auth.decorators import login_required, user_passes_test
+from django.http import HttpResponse
+from django.shortcuts import render, get_object_or_404
+from core.models import Blog
+
+
+def listing(request):
+    data = {
+        "blogs": Blog.objects.all(),
+    }
+
+    return render(request, "listing.html", data)
+
+
+def view_blog(request, blog_id):
+    blog = get_object_or_404(Blog, id=blog_id)
+    data = {
+        "blog": blog,
+    }
+
+    return render(request, "view_blog.html", data)
+
+
+def see_request(request):
+    text = f"""
+        Some attributes of the HttpRequest object:
+
+        scheme: {request.scheme}
+        path:   {request.path}
+        method: {request.method}
+        GET:    {request.GET}
+        user:   {request.user}
+    """
+
+    return HttpResponse(text, content_type="text/plain")
+
+
+def user_info(request):
+    text = f"""
+        Selected HttpRequest.user attributes:
+
+        username:     {request.user.username}
+        is_anonymous: {request.user.is_anonymous}
+        is_staff:     {request.user.is_staff}
+        is_superuser: {request.user.is_superuser}
+        is_active:    {request.user.is_active}
+    """
+
+    return HttpResponse(text, content_type="text/plain")
+
+
+@login_required
+def private_place(request):
+    return HttpResponse("Shhh, members only!", content_type="text/plain")
+
+
+@user_passes_test(lambda user: user.is_staff)
+def staff_place(request):
+    return HttpResponse("Employees must wash hands", content_type="text/plain")
+
+
+@login_required
+def add_messages(request):
+    username = request.user.username
+    messages.add_message(request, messages.INFO, f"Hello {username}")
+    messages.add_message(request, messages.WARNING, "DANGER WILL ROBINSON")
+
+    return HttpResponse("Messages added", content_type="text/plain")

django-view-auth/Blog/manage.py

+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "Blog.settings")
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == "__main__":
+    main()

django-view-auth/Blog/resetdb.sh

+#!/bin/bash
+
+find . -name "*.pyc" -exec rm {} \;
+rm db.sqlite3
+
+python manage.py makemigrations core
+python manage.py migrate
+python manage.py loaddata core

django-view-auth/Blog/runserver.sh

+#!/bin/bash
+
+python manage.py runserver

django-view-auth/Blog/templates/base.html

+<html>
+<body>
+
+{% block content %}
+{% endblock content %}
+
+</body>
+</html>

django-view-auth/Blog/templates/listing.html

+{% extends "base.html" %}
+
+{% block content %}
+<h1>Blog Listing</h1>
+
+{% if messages %}
+<ul class="messages" style="background-color:#ccc">
+  {% for message in messages %}
+    <li {% if message.tags %} class="{{ message.tags }}" {% endif %}>
+      {{ message }}
+    </li>
+  {% endfor %}
+</ul>
+{% endif %}
+
+<ul>
+{% for blog in blogs %}
+  <li> <a href="{% url 'view_blog' blog.id %}">{{blog.title}}</a> </li>
+{% endfor %}
+</ul>
+{% endblock content %}

django-view-auth/Blog/templates/registration/login.html

+{% extends 'base.html' %}
+
+{% block content %}
+<h1>Login</h1>
+
+<form method="post">
+    {% csrf_token %}
+    {{ form.as_p }}
+    <input type="submit" value="Login">
+</form>
+
+<a href="{% url 'listing' %}">All Blogs</a>
+{% endblock %}

django-view-auth/Blog/templates/view_blog.html

+{% extends "base.html" %}
+
+{% block content %}
+<h1>{{blog.title}}</h1>
+
+{{blog.content|safe}}
+
+<hr/>
+
+<a href="{% url 'listing' %}">All Blogs</a>
+{% endblock content %}

django-view-auth/README.md

+# Get Started With Django Part 3: Django View Authorization, Code Examples
+
+This folder contains the sample code for [Get Started With Django Part 3: Django View Authorization](https://realpython.com/django-view-authorization/).
+
+The code was tested with Python 3.8 and Django 3.0.7. To install the same version, use:
+
+    python -m pip install -r requirements.txt
+
+This tutorial uses the Django admin, and comes with some sample data. To get going you will need to run the following commands:
+
+    cd Blog
+    python manage.py migrate
+    python manage.py createsuperuser
+    python manage.py loaddata core.json
+
+Once those commands are complete, you can run the Django development server:
+
+    python manage.py runserver
+
+With the server running, visit `http://127.0.0.1:8000` in your web browser to see the results.

django-view-auth/requirements.txt

+Django==3.0.7

flask-connexion-rest/version_4/people.py

@@ -90,7 +90,7 @@ def create(person):
     else:
         abort(
             406,
-            "Peron with last name {lname} already exists".format(lname=lname),
+            "Person with last name {lname} already exists".format(lname=lname),
         )
 
 

intro-to-threading/prodcom_event.py

@@ -7,7 +7,9 @@ import time
 
 
 class Pipeline:
-    """Class to allow a single element pipeline between producer and consumer.
+    """
+    Class to allow a single element pipeline
+    between producer and consumer.
     """
 
     def __init__(self):

intro-to-threading/prodcom_lock.py

@@ -8,7 +8,9 @@ SENTINEL = object()
 
 
 class Pipeline:
-    """Class to allow a single element pipeline between producer and consumer.
+    """
+    Class to allow a single element pipeline
+    between producer and consumer.
     """
 
     def __init__(self):

nlp-sentiment-analysis/README.md

+# Use Sentiment Analysis With Python to Classify Reviews
+
+Resources and materials for Real Python's [Use Sentiment Analysis With Python to Classify Reviews](https://realpython.com/use-sentiment-analysis-python-classify-movie-reviews/) tutorial.
+
+## Installation
+
+Create and activate a new virtual environment:
+
+```shell
+$ python -m venv .venv
+$ source .venv/bin/activate
+```
+
+Install Python dependencies into the active virtual environment:
+
+```shell
+(.venv) $ python -m pip install -r requirements.txt
+```
+
+Download English model for spaCy:
+
+```shell
+(.venv) $ python -m spacy download en_core_web_sm
+```
+
+Download and extract the [Large Movie Review Dataset](https://ai.stanford.edu/~amaas/data/sentiment/) compiled by [Andrew Maas](http://www.andrew-maas.net/):
+
+```shell
+$ curl -s https://ai.stanford.edu/~amaas/data/sentiment/aclImdb_v1.tar.gz | tar xvz
+```
+
+## Usage
+
+Get the sentiment of a movie review stored in the `TEST_REVIEW` variable:
+
+```shell
+(.venv) $ python sentiment_analyzer.py
+```

nlp-sentiment-analysis/requirements.txt

+pandas==1.1.2
+spacy==2.3.2

nlp-sentiment-analysis/sentiment_analyzer.py

+import os
+import random
+import spacy
+from spacy.util import minibatch, compounding
+import pandas as pd
+
+
+TEST_REVIEW = """
+Transcendently beautiful in moments outside the office, it seems almost
+sitcom-like in those scenes. When Toni Colette walks out and ponders
+life silently, it's gorgeous.<br /><br />The movie doesn't seem to decide
+whether it's slapstick, farce, magical realism, or drama, but the best of it
+doesn't matter. (The worst is sort of tedious - like Office Space with less
+humor.)
+"""
+
+
+eval_list = []
+
+
+def train_model(
+    training_data: list, test_data: list, iterations: int = 20
+) -> None:
+    # Build pipeline
+    nlp = spacy.load("en_core_web_sm")
+    if "textcat" not in nlp.pipe_names:
+        textcat = nlp.create_pipe(
+            "textcat", config={"architecture": "simple_cnn"}
+        )
+        nlp.add_pipe(textcat, last=True)
+    else:
+        textcat = nlp.get_pipe("textcat")
+
+    textcat.add_label("pos")
+    textcat.add_label("neg")
+
+    # Train only textcat
+    training_excluded_pipes = [
+        pipe for pipe in nlp.pipe_names if pipe != "textcat"
+    ]
+    with nlp.disable_pipes(training_excluded_pipes):
+        optimizer = nlp.begin_training()
+        # Training loop
+        print("Beginning training")
+        print("Loss\tPrecision\tRecall\tF-score")
+        batch_sizes = compounding(
+            4.0, 32.0, 1.001
+        )  # A generator that yields infinite series of input numbers
+        for i in range(iterations):
+            print(f"Training iteration {i}")
+            loss = {}
+            random.shuffle(training_data)
+            batches = minibatch(training_data, size=batch_sizes)
+            for batch in batches:
+                text, labels = zip(*batch)
+                nlp.update(text, labels, drop=0.2, sgd=optimizer, losses=loss)
+            with textcat.model.use_params(optimizer.averages):
+                evaluation_results = evaluate_model(
+                    tokenizer=nlp.tokenizer,
+                    textcat=textcat,
+                    test_data=test_data,
+                )
+                print(
+                    f"{loss['textcat']}\t{evaluation_results['precision']}"
+                    f"\t{evaluation_results['recall']}"
+                    f"\t{evaluation_results['f-score']}"
+                )
+
+    # Save model
+    with nlp.use_params(optimizer.averages):
+        nlp.to_disk("model_artifacts")
+
+
+def evaluate_model(tokenizer, textcat, test_data: list) -> dict:
+    reviews, labels = zip(*test_data)
+    reviews = (tokenizer(review) for review in reviews)
+    true_positives = 0
+    false_positives = 1e-8  # Can't be 0 because of presence in denominator
+    true_negatives = 0
+    false_negatives = 1e-8
+    for i, review in enumerate(textcat.pipe(reviews)):
+        true_label = labels[i]["cats"]
+        for predicted_label, score in review.cats.items():
+            # Every cats dictionary includes both labels, you can get all
+            # the info you need with just the pos label
+            if predicted_label == "neg":
+                continue
+            if score >= 0.5 and true_label["pos"]:
+                true_positives += 1
+            elif score >= 0.5 and true_label["neg"]:
+                false_positives += 1
+            elif score < 0.5 and true_label["neg"]:
+                true_negatives += 1
+            elif score < 0.5 and true_label["pos"]:
+                false_negatives += 1
+    precision = true_positives / (true_positives + false_positives)
+    recall = true_positives / (true_positives + false_negatives)
+
+    if precision + recall == 0:
+        f_score = 0
+    else:
+        f_score = 2 * (precision * recall) / (precision + recall)
+    return {"precision": precision, "recall": recall, "f-score": f_score}
+
+
+def test_model(input_data: str = TEST_REVIEW):
+    #  Load saved trained model
+    loaded_model = spacy.load("model_artifacts")
+    # Generate prediction
+    parsed_text = loaded_model(input_data)
+    # Determine prediction to return
+    if parsed_text.cats["pos"] > parsed_text.cats["neg"]:
+        prediction = "Positive"
+        score = parsed_text.cats["pos"]
+    else:
+        prediction = "Negative"
+        score = parsed_text.cats["neg"]
+    print(
+        f"Review text: {input_data}\nPredicted sentiment: {prediction}"
+        f"\tScore: {score}"
+    )
+
+
+def load_training_data(
+    data_directory: str = "aclImdb/train", split: float = 0.8, limit: int = 0
+) -> tuple:
+    # Load from files
+    reviews = []
+    for label in ["pos", "neg"]:
+        labeled_directory = f"{data_directory}/{label}"
+        for review in os.listdir(labeled_directory):
+            if review.endswith(".txt"):
+                with open(f"{labeled_directory}/{review}") as f:
+                    text = f.read()
+                    text = text.replace("<br />", "\n\n")
+                    if text.strip():
+                        spacy_label = {
+                            "cats": {
+                                "pos": "pos" == label,
+                                "neg": "neg" == label,
+                            }
+                        }
+                        reviews.append((text, spacy_label))
+    random.shuffle(reviews)
+
+    if limit:
+        reviews = reviews[:limit]
+    split = int(len(reviews) * split)
+    return reviews[:split], reviews[split:]
+
+
+if __name__ == "__main__":
+    train, test = load_training_data(limit=25)
+    print("Training model")
+    train_model(train, test)
+    df = pd.DataFrame(eval_list)
+    pd.DataFrame.plot(df)
+    print("Testing model")
+    test_model()

pandas-gradebook-project/02-merging-dataframes.py

@@ -48,7 +48,10 @@ for file_path in DATA_FOLDER.glob("quiz_*_grades.csv"):
 # ------------------------
 
 final_data = pd.merge(
-    roster, hw_exam_grades, left_index=True, right_index=True,
+    roster,
+    hw_exam_grades,
+    left_index=True,
+    right_index=True,
 )
 final_data = pd.merge(
     final_data, quiz_grades, left_on="Email Address", right_index=True

pandas-gradebook-project/03-calculating-grades.py

@@ -49,7 +49,10 @@ for file_path in DATA_FOLDER.glob("quiz_*_grades.csv"):
 # ------------------------
 
 final_data = pd.merge(
-    roster, hw_exam_grades, left_index=True, right_index=True,
+    roster,
+    hw_exam_grades,
+    left_index=True,
+    right_index=True,
 )
 final_data = pd.merge(
     final_data, quiz_grades, left_on="Email Address", right_index=True

pandas-gradebook-project/04-grouping-the-data.py

@@ -49,7 +49,10 @@ for file_path in DATA_FOLDER.glob("quiz_*_grades.csv"):
 # ------------------------
 
 final_data = pd.merge(
-    roster, hw_exam_grades, left_index=True, right_index=True,
+    roster,
+    hw_exam_grades,
+    left_index=True,
+    right_index=True,
 )
 final_data = pd.merge(
     final_data, quiz_grades, left_on="Email Address", right_index=True

pandas-gradebook-project/05-plotting-summary-statistics.py

@@ -51,7 +51,10 @@ for file_path in DATA_FOLDER.glob("quiz_*_grades.csv"):
 # ------------------------
 
 final_data = pd.merge(
-    roster, hw_exam_grades, left_index=True, right_index=True,
+    roster,
+    hw_exam_grades,
+    left_index=True,
+    right_index=True,
 )
 final_data = pd.merge(
     final_data, quiz_grades, left_on="Email Address", right_index=True

pandas-gradebook-project/06-final-gradebook.py

@@ -43,7 +43,10 @@ for file_path in DATA_FOLDER.glob("quiz_*_grades.csv"):
     quiz_grades = pd.concat([quiz_grades, quiz], axis=1)
 
 final_data = pd.merge(
-    roster, hw_exam_grades, left_index=True, right_index=True,
+    roster,
+    hw_exam_grades,
+    left_index=True,
+    right_index=True,
 )
 final_data = pd.merge(
     final_data, quiz_grades, left_on="Email Address", right_index=True

python-bindings/overview_article/README.md

+# Real Python - Python Bindings Sample Code Repo
+
+This is the repo to accompany the [Python Bindings](https://realpython.com/python-bindings-overview/) article.
+
+To be able to run the code, you must first install the requirements:
+
+```console
+$ python -m pip install -r requirements.txt
+```
+This should be done inside a virtual environment.
+
+Once that is installed, you can use the invoke tool mentioned in the article to build and run the tests. See the tasks.py file or run invoke --list to get more details.
\ No newline at end of file

python-bindings/overview_article/cffi_test.py

 #!/usr/bin/env python3
+# IDE might complain with "no module found" here, even when it exists
 import cffi_example
 
 if __name__ == "__main__":

python-bindings/overview_article/cmult.h

-float cmult(int int_param, float float_param);
+#ifdef _MSC_VER
+    #define EXPORT_SYMBOL __declspec(dllexport)
+#else
+    #define EXPORT_SYMBOL
+#endif
+
+EXPORT_SYMBOL float cmult(int int_param, float float_param);
\ No newline at end of file

python-bindings/overview_article/ctypes_test.py

 #!/usr/bin/env python
 """ Simple examples of calling C functions through ctypes module. """
 import ctypes
-import pathlib
-
+import sys
 
 if __name__ == "__main__":
     # Load the shared library into c types.
-    libname = pathlib.Path().absolute() / "libcmult.so"
-    c_lib = ctypes.CDLL(libname)
+    if sys.platform.startswith("win"):
+        c_lib = ctypes.CDLL("cmult.dll")
+    else:
+        c_lib = ctypes.CDLL("libcmult.so")
 
     # Sample data for our call:
     x, y = 6, 2.3

python-bindings/overview_article/tasks.py

 """ Task definitions for invoke command line utility for python bindings
-    overview article. """
+    overview article.
+"""
 import cffi
 import invoke
 import pathlib
+import sys
+import os
+import shutil
+import re
+import glob
+
+on_win = sys.platform.startswith("win")
 
 
 @invoke.task
 def clean(c):
     """ Remove any built objects """
-    for pattern in ["*.o", "*.so", "cffi_example* cython_wrapper.cpp"]:
-        c.run("rm -rf {}".format(pattern))
+    for file_pattern in (
+        "*.o",
+        "*.so",
+        "*.obj",
+        "*.dll",
+        "*.exp",
+        "*.lib",
+        "*.pyd",
+        "cffi_example*",  # Is this a dir?
+        "cython_wrapper.cpp",
+    ):
+        for file in glob.glob(file_pattern):
+            os.remove(file)
+    for dir_pattern in "Release":
+        for dir in glob.glob(dir_pattern):
+            shutil.rmtree(dir)
 
 
 def print_banner(msg):
@@ -17,32 +39,55 @@ def print_banner(msg):
     print("= {} ".format(msg))
 
 
-@invoke.task
-def build_cmult(c):
+@invoke.task()
+def build_cmult(c, path=None):
     """ Build the shared library for the sample C code """
-    print_banner("Building C Library")
-    invoke.run("gcc -c -Wall -Werror -fpic cmult.c -I /usr/include/python3.7")
-    invoke.run("gcc -shared -o libcmult.so cmult.o")
-    print("* Complete")
+    # Moving this type hint into signature causes an error (???)
+    c: invoke.Context
+    if on_win:
+        if not path:
+            print("Path is missing")
+        else:
+            # Using c.cd didn't work with paths that have spaces :/
+            path = f'"{path}vcvars32.bat" x86'  # Enter the VS venv
+            path += f'&& cd "{os.getcwd()}"'  # Change to current dir
+            path += "&& cl /LD cmult.c"  # Compile
+            # Uncomment line below, to suppress stdout
+            # path = path.replace("&&", " >nul &&") + " >nul"
+            c.run(path)
+    else:
+        print_banner("Building C Library")
+        cmd = "gcc -c -Wall -Werror -fpic cmult.c -I /usr/include/python3.7"
+        invoke.run(cmd)
+        invoke.run("gcc -shared -o libcmult.so cmult.o")
+        print("* Complete")
 
 
-@invoke.task(build_cmult)
+@invoke.task()
 def test_ctypes(c):
     """ Run the script to test ctypes """
     print_banner("Testing ctypes Module")
-    invoke.run("python3 ctypes_test.py", pty=True)
+    # pty and python3 didn't work for me (win).
+    if on_win:
+        invoke.run("python ctypes_test.py")
+    else:
+        invoke.run("python3 ctypes_test.py", pty=True)
 
 
-@invoke.task(build_cmult)
+@invoke.task()
 def build_cffi(c):
     """ Build the CFFI Python bindings """
     print_banner("Building CFFI Module")
     ffi = cffi.FFI()
 
-    this_dir = pathlib.Path().absolute()
+    this_dir = pathlib.Path().resolve()
     h_file_name = this_dir / "cmult.h"
     with open(h_file_name) as h_file:
-        ffi.cdef(h_file.read())
+        # cffi does not like our preprocessor directives, so we remove them
+        lns = h_file.read().splitlines()
+        flt = filter(lambda ln: not re.match(r" *#", ln), lns)
+        flt = map(lambda ln: ln.replace("EXPORT_SYMBOL ", ""), flt)
+        ffi.cdef(str("\n").join(flt))
 
     ffi.set_source(
         "cffi_example",
@@ -66,7 +111,7 @@ def build_cffi(c):
 def test_cffi(c):
     """ Run the script to test CFFI """
     print_banner("Testing CFFI Module")
-    invoke.run("python3 cffi_test.py", pty=True)
+    invoke.run("python cffi_test.py", pty=not on_win)
 
 
 @invoke.task()

python-menus-toolbars/MIT.txt

+The MIT License (MIT)
+
+Copyright (c) 2020 Leodanis Pozo Ramos
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

python-menus-toolbars/README.md

+# Sample PyQt Application
+
+A sample GUI application that shows how to create and use menus, toolbars, and status bars using Python and PyQt.
+
+## How to Run this Application
+
+To run this application, you need to [install `PyQt5`](https://realpython.com/python-pyqt-gui-calculator/#installing-pyqt) on your Python environment. To do that, you can run the following commands in a terminal or command prompt:
+
+```sh
+$ pip3 install PyQt5
+```
+
+Once you have [PyQt](https://www.riverbankcomputing.com/static/Docs/PyQt5/) installed, you can run the application by executing the following command:
+
+```sh
+$ python3 sample-app.py
+```
+
+This command will launch the application, so you'll be able to experiment with it.
+
+## About the Author
+
+Leodanis Pozo Ramos – [@lpozo78](https://twitter.com/lpozo78) – lpozor78@gmail.com
+
+## License
+
+- This application is distributed under the MIT license. See `LICENSE` for details.
+
+- The set of icons used in this application are part of the [TurkinOS](https://github.com/llamaret/turkinos-icon) icon theme, which is distributed under the [GPL v3.0 license](https://github.com/llamaret/turkinos-icon/blob/master/LICENSE). See `resources/LICENSE` for details.
\ No newline at end of file

python-menus-toolbars/resources.qrc

+<!DOCTYPE RCC><RCC version="1.0">
+<qresource>
+    <file alias="file-new.svg">resources/file-new.svg</file>
+    <file alias="file-open.svg">resources/file-open.svg</file>
+    <file alias="file-save.svg">resources/file-save.svg</file>
+    <file alias="file-exit.svg">resources/file-exit.svg</file>
+    <file alias="edit-copy.svg">resources/edit-copy.svg</file>
+    <file alias="edit-cut.svg">resources/edit-cut.svg</file>
+    <file alias="edit-paste.svg">resources/edit-paste.svg</file>
+    <file alias="help-content.svg">resources/help-content.svg</file>
+</qresource>
+</RCC>

python-menus-toolbars/resources/edit-copy.svg

+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 22 22">
+ <defs id="defs3051">
+   <style type="text/css" id="current-color-scheme">
+     .ColorScheme-Text {
+       color:#4d4d4d;
+     }
+     </style>
+ </defs>
+   <path
+      style="fill:currentColor;fill-opacity:1;stroke:none"
+      d="m14.999993 6.0000017h-10.999988c-.5520048 0-1.000005.4480002-1.000005.9999916v11.0000017c0 .552005.4480002 1.000005 1.000005 1.000005h10.999988c.552005 0 1.000005-.448 1.000005-1.000005v-11.0000017c0-.5519914-.448-.9999916-1.000005-.9999916zm3.000002-3.0000017h-9.9999967c-.5520048 0-1.000005.4480002-1.000005 1.000005v.9999916h1.000005v-.5000025c0-.2759957.2240068-.4999891.5000025-.4999891h8.9999912c.27601 0 .500003.2239934.500003.4999891v9.0000049c0 .275996-.223993.500003-.500003.500003h-.499989v.999991h.999992c.552005 0 1.000005-.448 1.000005-.999991v-9.999997c0-.5520048-.448-1.000005-1.000005-1.000005z"
+      class="ColorScheme-Text" />
+</svg> 

python-menus-toolbars/resources/edit-cut.svg

+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 22 22">
+ <defs id="defs3051">
+   <style type="text/css" id="current-color-scheme">
+     .ColorScheme-Text {
+       color:#4d4d4d;
+     }
+     </style>
+ </defs>
+   <path
+      style="fill:currentColor;fill-opacity:1;stroke:none"
+      d="m7.0136719 2-.4355469.7753906c-.2699231.4812667-.5038694.7087891-.6289062 1.1367188-.0625185.2139647-.0612584.4699226.0019531.7011718.0632171.2312494.1726285.4527981.3261719.7265626l3.3945312 6.0625002-1.7148438 3.023437c-.4483616-.277461-.8911737-.591797-1.4550781-.591797-1.6582865 0-3.0019531 1.388975-3.0019531 3.083985 0 1.695008 1.3436663 3.082031 3.0019531 3.082031 1.658287 0 3.0019532-1.387023 3.0019531-3.082031 0-.133955-.0209824-.259363-.0371093-.386719.4622484-1.003569.8985411-1.788627 1.8085941-2.248047.003037-.003375.002934-.004437.005859-.007812l1.253906 2.238281c-.017223.134034-.039062.265801-.039062.404297 0 1.695008 1.343665 3.082031 3.001953 3.082031 1.658287 0 3.001953-1.387023 3.001953-3.082031 0-1.69501-1.343667-3.083985-3.001953-3.083985-.56176 0-1.004412.308543-1.451172.583985l-1.708984-3.015625 3.398437-6.0625002v-.0019532c.152934-.2728193.261159-.4939397.324219-.7246094.063214-.2312492.066332-.4872071.003906-.7011718-.125138-.4278882-.358984-.6554521-.628906-1.1367188l-.435547-.7753906-3.994141 7.0488281zm-.5117188 13.884766c.5564078 0 .9960938.448401.9960938 1.033203s-.439686 1.03125-.9960938 1.03125-.9941406-.446448-.9941406-1.03125c0-.584803.4377328-1.033203.9941406-1.033203zm8.9960939 0c .556407 0 .99414.448401.994141 1.033203 0 .584802-.437734 1.03125-.994141 1.03125-.556409 0-.996094-.446448-.996094-1.03125 0-.584803.439685-1.033203.996094-1.033203z"
+      class="ColorScheme-Text" />
+</svg> 

python-menus-toolbars/resources/edit-paste.svg

+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 22 22">
+ <defs id="defs3051">
+   <style type="text/css" id="current-color-scheme">
+     .ColorScheme-Text {
+       color:#4d4d4d;
+     }
+     </style>
+ </defs>
+   <path
+      style="fill:currentColor;fill-opacity:1;stroke:none"
+      d="m14.12662 8.00521h-.9452v-2.22935c0-.23294-.18815-.4217-.42014-.4217h-.45273l-.90589-3.0529c-.053-.17871-.21679-.30126-.40266-.30126-.18578 0-.34963.12255-.40266.30126l-.90589 3.0529h-.45273c-.23199 0-.42014.18876-.42014.4217v2.22942h-.9452c-1.03295 0-1.87338.84348-1.87338 1.88035v8.23403c0 1.03686.84035 1.88034 1.87338 1.88034h6.25324c1.03295 0 1.87338-.84348 1.87338-1.88034v-8.23403c0-1.03696-.84035-1.88042-1.87338-1.88042z"
+      class="ColorScheme-Text" />
+</svg> 

python-menus-toolbars/resources/file-exit.svg

+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 22 22">
+ <defs id="defs3051">
+   <style type="text/css" id="current-color-scheme">
+     .ColorScheme-Text {
+       color:#4d4d4d;
+     }
+     </style>
+ </defs>
+   <path
+      style="fill:currentColor;fill-opacity:1;stroke:none"
+      d="m17.927299 6.98434c-.715348-1.22562-1.685765-2.19604-2.911381-2.91138-1.225871-.71535-2.564127-1.07296-4.015662-1.07296-1.4514075 0-2.7900468.35761-4.0156625 1.07296-1.2257436.71522-2.1961612 1.68563-2.9115085 2.91138-.7154752 1.22574-1.073085 2.56438-1.073085 4.01566 0 1.45141.3577376 2.78979 1.0729571 4.01566.7153474 1.22549 1.685765 2.19604 2.9115085 2.91138 1.2257436.71535 2.5642551 1.07296 4.0156624 1.07296 1.451407 0 2.790046-.35761 4.015662-1.07296 1.225616-.71522 2.196033-1.68576 2.911381-2.91138.715219-1.22574 1.072829-2.56438 1.072829-4.01566 0-1.45141-.35761-2.79005-1.072701-4.01566zm-3.156351 5.90101c.131946.13181.198047.28831.198047.46884 0 .18743-.0661.34725-.198047.47907l-.937431.93756c-.131946.13195-.291637.19792-.4792.19792-.18053 0-.337025-.066-.468715-.19792l-1.885474-1.88547-1.8854742 1.88547c-.1319462.13195-.2881847.19792-.4687156.19792-.1875629 0-.3472535-.066-.4791996-.19792l-.9375589-.93756c-.1319462-.13182-.1979192-.29164-.1979192-.47907 0-.18053.065973-.33703.1979192-.46884l1.8854741-1.88535-1.8854741-1.88547c-.1319462-.13182-.1979192-.28819-.1979192-.46872 0-.18756.065973-.34725.1979192-.4792l.9375589-.93743c.1319461-.13195.2916367-.19792.4791996-.19792.1805309 0 .3367694.066.4687156.19792l1.8854742 1.88535 1.885474-1.88535c.13169-.13195.288185-.19792.468715-.19792.187563 0 .347254.066.4792.19792l.937431.93743c.131946.13195.198047.29164.198047.4792 0 .18053-.0661.3369-.198047.46872l-1.885346 1.88547z"
+      class="ColorScheme-Text" />
+</svg> 

python-menus-toolbars/resources/file-new.svg

+    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 22 22">
+ <defs id="defs3051">
+   <style type="text/css" id="current-color-scheme">
+     .ColorScheme-Text {
+       color:#4d4d4d;
+     }
+     </style>
+ </defs>
+   <path
+      style="fill:currentColor;fill-opacity:1;stroke:none"
+      d="m9.666667 3c-.246249 0-.444445.1981956-.444445.4444444v5.7777776h-5.7777776c-.2462222 0-.4444444.198222-.4444444.444445v2.666666c0 .246223.1982222.444445.4444444.444445h5.7777776v5.777778c0 .246248.198196.444444.444445.444444h2.666666c.246249 0 .444445-.198196.444445-.444444v-5.777778h5.777778c.246222 0 .444444-.198222.444444-.444445v-2.666666c0-.246223-.198222-.444445-.444444-.444445h-5.777778v-5.7777776c0-.2462488-.198196-.4444444-.444445-.4444444z"
+      class="ColorScheme-Text" />
+</svg> 

python-menus-toolbars/resources/file-open.svg

+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 22 22">
+ <defs id="defs3051">
+   <style type="text/css" id="current-color-scheme">
+     .ColorScheme-Text {
+       color:#4d4d4d;
+     }
+     </style>
+ </defs>
+   <path
+      style="fill:currentColor;fill-opacity:1;stroke:none"
+      d="m2.5000001 1034.3622c-.277 0-.5.223-.5.5v1.9609 1.0391 10.0391c0 .2557.2052456.4609.4609375.4609h17.0781244c.255692 0 .460938-.2052.460938-.4609v-11.0782c0-.2557-.205246-.4609-.460938-.4609h-8.181159c-.569865.017-.846295-.1321-1.097628-.3681l-1.1884019-1.21c-.16805-.2202-.294873-.4219-.571873-.4219z"
+      class="ColorScheme-Text" 
+      transform="matrix(.88888889 0 0 .88888889 1.222222 -914.87751)"/>
+</svg> 

python-menus-toolbars/resources/file-save.svg

+<svg viewBox="0 0 22 22" xmlns="http://www.w3.org/2000/svg">
+<defs id="defs">
+    <style type="text/css" id="current-color-scheme">
+        .ColorScheme-Text { color: #4d4d4d; }
+    </style>
+</defs>
+<path style="fill:currentColor;fill-opacity;stroke:none" class="ColorScheme-Text" d="m3.6679688 3c-.3691339 0-.6679688.2988749-.6679688.6679688v14.6640622c0 .369134.2988349.667969.6679688.667969h14.6640622c.369134 0 .667969-.298835.667969-.667969v-11.5585935c0-.1772133-.069939-.3473157-.195312-.4726563l-3.105469-3.1054687c-.12534-.1253333-.295351-.1953125-.472657-.1953125zm1.9707031 1.5273438h9.1777341v4.9003906h-9.1777341zm5.5703121.4726562c-.115073 0-.208984.1073944-.208984.2402344v3.5195312c0 .13288.093911.2402344.208984.2402344h1.582032c.115073 0 .208984-.1073544.208984-.2402344v-3.5195312c0-.13284-.093911-.2402344-.208984-.2402344z" transform="matrix(1.000000005 0 0 1.000000005 .000001275238 .00000172266)"/></svg>

python-menus-toolbars/resources/help-content.svg

+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 22 22">
+ <defs id="defs3051">
+   <style type="text/css" id="current-color-scheme">
+     .ColorScheme-Text {
+       color:#4d4d4d;
+     }
+     </style>
+ </defs>
+   <path
+      style="fill:currentColor;fill-opacity:1;stroke:none"
+      d="m10.999999 3.000002a8 8 0 0 0 -8 8 8 8 0 0 0 8 8 8 8 0 0 0 8-8 8 8 0 0 0 -8-8zm-.199219 3.5a1 1 0 0 1 1 1 1 1 0 0 1 -1 1 1 1 0 0 1 -.9999998-1 1 1 0 0 1  .9999998-1zm-.107422 3h .212891c.356143 0 .644531.2864351.644531.642578v4.714844c0 .356143-.288388.642578-.644531.642578h-.212891c-.356143 0-.642578-.286435-.642578-.642578v-4.714844c0-.3561429.286435-.642578.642578-.642578z"
+      class="ColorScheme-Text" />
+</svg> 

python-menus-toolbars/sample-app.py

+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+"""Sample PyQt application."""
+
+import sys
+from functools import partial
+
+from PyQt5.QtCore import Qt
+from PyQt5.QtGui import QIcon, QKeySequence
+from PyQt5.QtWidgets import (
+    QAction,
+    QApplication,
+    QLabel,
+    QMainWindow,
+    QMenu,
+    QSpinBox,
+    QToolBar,
+)
+
+# NOTE: Uncomment this import to enable icons
+# import qrc_resources
+
+
+class Window(QMainWindow):
+    """Main Window."""
+
+    def __init__(self, parent=None):
+        """Initializer."""
+        super().__init__(parent)
+        self.setWindowTitle("Python Menus & Toolbars")
+        self.resize(400, 200)
+        self.centralWidget = QLabel("Hello, World")
+        self.centralWidget.setAlignment(Qt.AlignHCenter | Qt.AlignVCenter)
+        self.setCentralWidget(self.centralWidget)
+        self._createActions()
+        self._createMenuBar()
+        self._createToolBars()
+
+        # Uncomment the call to ._createContextMenu() below to create a context
+        # menu using menu policies. To test this out, you also need to
+        # comment .contextMenuEvent() and uncomment ._createContextMenu()
+
+        # self._createContextMenu()
+
+        self._connectActions()
+        self._createStatusBar()
+
+    def _createMenuBar(self):
+        menuBar = self.menuBar()
+        # File menu
+        fileMenu = QMenu("&File", self)
+        menuBar.addMenu(fileMenu)
+        fileMenu.addAction(self.newAction)
+        fileMenu.addAction(self.openAction)
+        # Open Recent submenu
+        self.openRecentMenu = fileMenu.addMenu("Open Recent")
+        fileMenu.addAction(self.saveAction)
+        # Separator
+        fileMenu.addSeparator()
+        fileMenu.addAction(self.exitAction)
+        # Edit menu
+        editMenu = menuBar.addMenu("&Edit")
+        editMenu.addAction(self.copyAction)
+        editMenu.addAction(self.pasteAction)
+        editMenu.addAction(self.cutAction)
+        # Separator
+        editMenu.addSeparator()
+        # Find and Replace submenu
+        findMenu = editMenu.addMenu("Find and Replace")
+        findMenu.addAction("Find...")
+        findMenu.addAction("Replace...")
+        # Help menu
+        helpMenu = menuBar.addMenu(QIcon(":help-content.svg"), "&Help")
+        helpMenu.addAction(self.helpContentAction)
+        helpMenu.addAction(self.aboutAction)
+
+    def _createToolBars(self):
+        # File toolbar
+        fileToolBar = self.addToolBar("File")
+        fileToolBar.setMovable(False)
+        fileToolBar.addAction(self.newAction)
+        fileToolBar.addAction(self.openAction)
+        fileToolBar.addAction(self.saveAction)
+        # Edit toolbar
+        editToolBar = QToolBar("Edit", self)
+        self.addToolBar(editToolBar)
+        editToolBar.addAction(self.copyAction)
+        editToolBar.addAction(self.pasteAction)
+        editToolBar.addAction(self.cutAction)
+        # Widgets
+        self.fontSizeSpinBox = QSpinBox()
+        self.fontSizeSpinBox.setFocusPolicy(Qt.NoFocus)
+        editToolBar.addWidget(self.fontSizeSpinBox)
+
+    def _createStatusBar(self):
+        self.statusbar = self.statusBar()
+        # Temporary message
+        self.statusbar.showMessage("Ready", 3000)
+        # Permanent widget
+        self.wcLabel = QLabel(f"{self.getWordCount()} Words")
+        self.statusbar.addPermanentWidget(self.wcLabel)
+
+    def _createActions(self):
+        # File actions
+        self.newAction = QAction(self)
+        self.newAction.setText("&New")
+        self.newAction.setIcon(QIcon(":file-new.svg"))
+        self.openAction = QAction(QIcon(":file-open.svg"), "&Open...", self)
+        self.saveAction = QAction(QIcon(":file-save.svg"), "&Save", self)
+        self.exitAction = QAction("&Exit", self)
+        # String-based key sequences
+        self.newAction.setShortcut("Ctrl+N")
+        self.openAction.setShortcut("Ctrl+O")
+        self.saveAction.setShortcut("Ctrl+S")
+        # Help tips
+        newTip = "Create a new file"
+        self.newAction.setStatusTip(newTip)
+        self.newAction.setToolTip(newTip)
+        self.newAction.setWhatsThis("Create a new and empty text file")
+        # Edit actions
+        self.copyAction = QAction(QIcon(":edit-copy.svg"), "&Copy", self)
+        self.pasteAction = QAction(QIcon(":edit-paste.svg"), "&Paste", self)
+        self.cutAction = QAction(QIcon(":edit-cut.svg"), "C&ut", self)
+        # Standard key sequence
+        self.copyAction.setShortcut(QKeySequence.Copy)
+        self.pasteAction.setShortcut(QKeySequence.Paste)
+        self.cutAction.setShortcut(QKeySequence.Cut)
+        # Help actions
+        self.helpContentAction = QAction("&Help Content...", self)
+        self.aboutAction = QAction("&About...", self)
+
+    # Uncomment this method to create a context menu using menu policies
+    # def _createContextMenu(self):
+    #     # Setting contextMenuPolicy
+    #     self.centralWidget.setContextMenuPolicy(Qt.ActionsContextMenu)
+    #     # Populating the widget with actions
+    #     self.centralWidget.addAction(self.newAction)
+    #     self.centralWidget.addAction(self.openAction)
+    #     self.centralWidget.addAction(self.saveAction)
+    #     self.centralWidget.addAction(self.copyAction)
+    #     self.centralWidget.addAction(self.pasteAction)
+    #     self.centralWidget.addAction(self.cutAction)
+
+    def contextMenuEvent(self, event):
+        # Context menu
+        menu = QMenu(self.centralWidget)
+        # Populating the menu with actions
+        menu.addAction(self.newAction)
+        menu.addAction(self.openAction)
+        menu.addAction(self.saveAction)
+        # Separator
+        separator = QAction(self)
+        separator.setSeparator(True)
+        menu.addAction(separator)
+        menu.addAction(self.copyAction)
+        menu.addAction(self.pasteAction)
+        menu.addAction(self.cutAction)
+        # Launching the menu
+        menu.exec(event.globalPos())
+
+    def _connectActions(self):
+        # Connect File actions
+        self.newAction.triggered.connect(self.newFile)
+        self.openAction.triggered.connect(self.openFile)
+        self.saveAction.triggered.connect(self.saveFile)
+        self.exitAction.triggered.connect(self.close)
+        # Connect Edit actions
+        self.copyAction.triggered.connect(self.copyContent)
+        self.pasteAction.triggered.connect(self.pasteContent)
+        self.cutAction.triggered.connect(self.cutContent)
+        # Connect Help actions
+        self.helpContentAction.triggered.connect(self.helpContent)
+        self.aboutAction.triggered.connect(self.about)
+        # Connect Open Recent to dynamically populate it
+        self.openRecentMenu.aboutToShow.connect(self.populateOpenRecent)
+
+    # Slots
+    def newFile(self):
+        # Logic for creating a new file goes here...
+        self.centralWidget.setText("<b>File > New</b> clicked")
+
+    def openFile(self):
+        # Logic for opening an existing file goes here...
+        self.centralWidget.setText("<b>File > Open...</b> clicked")
+
+    def saveFile(self):
+        # Logic for saving a file goes here...
+        self.centralWidget.setText("<b>File > Save</b> clicked")
+
+    def copyContent(self):
+        # Logic for copying content goes here...
+        self.centralWidget.setText("<b>Edit > Copy</b> clicked")
+
+    def pasteContent(self):
+        # Logic for pasting content goes here...
+        self.centralWidget.setText("<b>Edit > Pate</b> clicked")
+
+    def cutContent(self):
+        # Logic for cutting content goes here...
+        self.centralWidget.setText("<b>Edit > Cut</b> clicked")
+
+    def helpContent(self):
+        # Logic for launching help goes here...
+        self.centralWidget.setText("<b>Help > Help Content...</b> clicked")
+
+    def about(self):
+        # Logic for showing an about dialog content goes here...
+        self.centralWidget.setText("<b>Help > About...</b> clicked")
+
+    def populateOpenRecent(self):
+        # Step 1. Remove the old options from the menu
+        self.openRecentMenu.clear()
+        # Step 2. Dynamically create the actions
+        actions = []
+        filenames = [f"File-{n}" for n in range(5)]
+        for filename in filenames:
+            action = QAction(filename, self)
+            action.triggered.connect(partial(self.openRecentFile, filename))
+            actions.append(action)
+        # Step 3. Add the actions to the menu
+        self.openRecentMenu.addActions(actions)
+
+    def openRecentFile(self, filename):
+        # Logic for opening a recent file goes here...
+        self.centralWidget.setText(f"<b>{filename}</b> opened")
+
+    def getWordCount(self):
+        # Logic for computing the word count goes here...
+        return 42
+
+
+if __name__ == "__main__":
+    # Create the application
+    app = QApplication(sys.argv)
+    # Create and show the main window
+    win = Window()
+    win.show()
+    # Run the event loop
+    sys.exit(app.exec_())

python-practice-problems/README.md

+# Python Practice Problems
+
+Unittest stubs for ["Python Practice Problems."](https://realpython.com/python-practice-problems/)
+
+## Running the Tests
+
+To run the test for a given problem, use `unittest` from the Python standard library;
+
+```console
+$ python -m unittest integersums.py
+```
+
+The above example will run the unit tests for the first practice problem.
\ No newline at end of file

python-practice-problems/caesar.py

+#!/usr/bin/env python3
+""" Caesar Cipher
+    A caesar cipher is a simple substitution cipher where each letter of the
+    plain text is substituted with a letter found by moving 'n' places down the
+    alphabet. For an example, if the input plain text is:
+
+        abcd xyz
+
+    and the shift value, n, is 4. The encrypted text would be:
+
+        efgh bcd
+
+    You are to write a function which accepts two arguments, a plain-text
+    message and a number of letters to shift in the cipher. The function will
+    return an encrypted string with all letters being transformed while all
+    punctuation and whitespace remains unchanged.
+
+    Note: You can assume the plain text is all lowercase ascii, except for
+    whitespace and punctuation.
+"""
+import unittest
+
+
+def caesar(plain_text, shift_num=1):
+    # TODO: Your code goes here!
+    result = plain_text
+    return result
+
+
+class CaesarTestCase(unittest.TestCase):
+    def test_a(self):
+        start = "aaa"
+        result = caesar(start, 1)
+        self.assertEqual(result, "bbb")
+        result = caesar(start, 5)
+        self.assertEqual(result, "fff")
+
+    def test_punctuation(self):
+        start = "aaa.bbb"
+        result = caesar(start, 1)
+        self.assertEqual(result, "bbb.ccc")
+        result = caesar(start, -1)
+        self.assertEqual(result, "zzz.aaa")
+
+    def test_whitespace(self):
+        start = "aaa    bb b"
+        result = caesar(start, 1)
+        self.assertEqual(result, "bbb    cc c")
+        result = caesar(start, 3)
+        self.assertEqual(result, "ddd    ee e")
+
+    def test_wraparound(self):
+        start = "abc"
+        result = caesar(start, -1)
+        self.assertEqual(result, "zab")
+        result = caesar(start, -2)
+        self.assertEqual(result, "yza")
+        result = caesar(start, -3)
+        self.assertEqual(result, "xyz")
+
+        start = "xyz"
+        result = caesar(start, 1)
+        self.assertEqual(result, "yza")
+        result = caesar(start, 2)
+        self.assertEqual(result, "zab")
+        result = caesar(start, 3)
+        self.assertEqual(result, "abc")
+
+
+if __name__ == "__main__":
+    unittest.main()

python-practice-problems/integersums.py

+#!/usr/bin/env python3
+""" Sum of Integers Up To n
+    Write a function, add_it_up, which returns the sum of the integers from 0
+    to the single integer input parameter.
+
+    The function should return 0 if a non-integer is passed in.
+"""
+import unittest
+
+
+def add_it_up(n):
+    # TODO: Your code goes here!
+    return n
+
+
+class IntegerSumTestCase(unittest.TestCase):
+    def test_to_ten(self):
+        results = [0, 1, 3, 6, 10, 15, 21, 28, 36, 45]
+        for n in range(10):
+            self.assertEqual(add_it_up(n), results[n])
+
+    def test_string(self):
+        self.assertEqual(add_it_up("testing"), 0)
+
+    def test_float(self):
+        self.assertEqual(add_it_up(0.124), 0)
+
+    def test_negative(self):
+        self.assertEqual(add_it_up(-19), 0)
+
+
+if __name__ == "__main__":
+    unittest.main()

python-practice-problems/logparse.py

+#!/usr/bin/env python3
+""" log parser
+    Accepts a filename on the command line.  The file is a linux-like log file
+    from a system you are debugging.  Mixed in among the various statements are
+    messages indicating the state of the device.  They look like:
+        Jul 11 16:11:51:490 [139681125603136] dut: Device State: ON
+    The device state message has many possible values, but this program only
+    cares about three: ON, OFF, and ERR.
+
+    Your program will parse the given log file and print out a report giving
+    how long the device was ON, and the time stamp of any ERR conditions.
+"""
+
+
+if __name__ == "__main__":
+    # TODO: Your code goes here
+    print("There are no unit tests for logparse.")

python-practice-problems/sudokusolve.py

+#!/usr/bin/env python3
+""" Sudoku Solver
+    NOTE: A description of the Sudoku puzzle can be found at:
+
+        https://en.wikipedia.org/wiki/Sudoku
+
+    Given a string in SDM format, described below, write a program to find and
+    return the solution for the Sudoku puzzle given in the string. The solution
+    should be returned in the same SDM format as the input.
+
+    Some puzzles will not be solvable. In that case, return the string
+    "Unsolvable".
+
+    The general sdx format is described here:
+
+        http://www.sudocue.net/fileformats.php
+
+    For our purposes, each SDX string will be a sequence of 81 digits, one for
+    each position on the Sudoku puzzle. Known numbers will be given and unknown
+    positions will have a zero value.
+
+    For example, this string of digits (split onto two lines for readability):
+
+        0040060790000006020560923000780610305090004
+             06020540890007410920105000000840600100
+
+    represents this starting Sudoku puzzle:
+
+             0 0 4   0 0 6   0 7 9
+             0 0 0   0 0 0   6 0 2
+             0 5 6   0 9 2   3 0 0
+
+             0 7 8   0 6 1   0 3 0
+             5 0 9   0 0 0   4 0 6
+             0 2 0   5 4 0   8 9 0
+
+             0 0 7   4 1 0   9 2 0
+             1 0 5   0 0 0   0 0 0
+             8 4 0   6 0 0   1 0 0
+
+    The unit tests provide may take a while to run, so be patient.
+"""
+import unittest
+
+
+def sudoku_solve(input_string):
+    # TODO: Your code goes here!
+    return input_string
+
+
+class SudokuSolverTestCase(unittest.TestCase):
+    problems = [
+        "00400607900000060205609230007806103050900040602054089000741092010500"
+        "0000840600100",
+        "01640000020000900040000006207023010010000000300308704096000000500080"
+        "0007000006820",
+        "04900860500300700000000003000040080006081502000100900001000000000060"
+        "0400804500390",
+        "76050000000006000800000040320040080008000003000500100780900000060001"
+        "0000000003041",
+        "00060500000302080004509027050000000106200054040000000709806045000604"
+        "0700000203000",
+        "40900070500001000000620780020000000900370420080000000400280150000006"
+        "0000905000406",
+        "00001003004007050100200800668000000300030200030000004520050080080104"
+        "0020090020000",
+        "08007003026005001800000040000060200039001008600070900000400080081004"
+        "0052050090070",
+        "00009300600080090002000610000008005300600020037005000000250004000100"
+        "9000700130007",
+    ]
+    expected = [
+        "28413657991375468275689234147896123553928741662154389736741592819532"
+        "8764842679153",
+        "31645297828567931449731856287923415614296578365318724996872143552184"
+        "3697734596821",
+        "14923867562395714875814623993547286146781592328136975431679458259268"
+        "3417874521396",
+        "76354812942136975895817246329743681518679523434582169781925437663491"
+        "7582572683941",
+        "82967531467312489514539827658743692196281754343195268739876145221654"
+        "9738754283169",
+        "41963872572851964353624789125418637919375426886792315464289153737146"
+        "5982985372416",
+        "76891543294327658151243879668519427317435296832968714523756981485174"
+        "3629496821357",
+        "48197623526745391893582146717863254939251478654678932172416589381934"
+        "7652653298174",
+        "Unsolvable",
+    ]
+
+    def test_solver(self):
+        for index, problem in enumerate(self.problems):
+            print(f"Testing puzzle {index+1}")
+            result = sudoku_solve(problem)
+            self.assertEqual(result, self.expected[index])
+
+
+if __name__ == "__main__":
+    unittest.main()

python-sqlite-sqlalchemy/README.md

-# Python / Sqlite /SqlAlchemy article
+# Python / SQLite /SQLAlchemy article
 
-This repository contains the content and example code 
-for the python/sqlite/sqlaclchemy article I'm writing 
+This repository contains the content and example code
+for the Python / SQLite / SQLAlchemy article I'm writing
 for Real Python.
 
 This project was built using Python 3.8.0
 
+## Python Virtualenv
+
+I use the `pyenv` tool to install Python versions on my Mac. I find it a very useful tool, and the instructions that follow use it, and are based on having Python version 3.8.0 installed using the following command:
+
+```shell
+$ pyenv install 3.8.0
+```
+
 ## Installing The Project
 
-From the main folder take the following steps:
+From the main folder take the following steps (on a Mac):
 
 * Install a Python virtual environment for this project
+  * `pyenv local 3.8.0`
+  * `python -m venv .venv`
 * Activate the virtual environment
+  * `source .venv/bin/activate`
 * Install the project:
-
-```shell script
-python -m pip install -e .
-```
-    
\ No newline at end of file
+  * `python -m pip install -e .`

python-sqlite-sqlalchemy/project/build_data/README.md

 # Build Files Used By The Examples
 
 The code in this directory builds the various data files used
-by the example programs. There are three build programs:
+by the example programs. There is one build program:
+
+* build_author_book_publisher_sqlite.py
 
- * build_temp_data_csv.py
- * build_temp_data_sqlite.py
- * build_author_book_publisher_sqlite.py
- 
-## Build the Temperature CSV File
- 
- The build_temp_data_csv.py file builds a CSV data file
- (temp_data.csv) in the data directory
- containing temperature samples taken by students in a class.
- The top row contains the labels, the students name followed
- by a date value for each Wednesday of the week for a year.
- 
- It then creates data for each sample based on a table of 
- temperature data, +/- 10 to make the data look variable
- and reasonable.
- 
-## Build the Temperature Database File
- 
- The build_temp_data_sqlite.py file builds a Sqlite database
- from the previously created temp_data.csv file called 
- temp_data.db in the data directory. 
- 
 ## Build the Author / Book / Publisher Database File
- 
- The build_author_book_publisher_sqlite.py file builds
- a database from the data/author_book_publisher.csv file.
- This database contains the tables necessary to describe 
- the data and the relationships between the data necessary
- for the examples.
- 
+
+The build_author_book_publisher_sqlite.py file builds
+a database from the `data/author_book_publisher.csv` file.
+This database contains the rows of comma delimited text to describe
+the data and the relationships between the data necessary
+for the examples.
+
 ## Directory Structure
- 
- The directory structure is set up in such a way the
- build programs (as well as the examples) can find the
- data files needed for each one.
- 
+
+The directory structure is set up in such a way the
+build programs (as well as the examples) can find the
+data files needed for each one.
+
 ## Executing the Programs
- 
-  * Activate your Python virtualenv
-  * cd into the build/code directory
-  * python build_temp_data_csv.py - builds the csv data file
-  * python build_temp_data_sqlite.py - builds the temperature data from the csv file
-  * python build_author_book_publisher_sqlite.py - builds the author_book_publisher.db database file
+
+Follow these steps to build the `data/author_book_publisher.db` database file.
+
+* Activate your Python virtualenv
+* cd into the build/code directory
+* python build_author_book_publisher_sqlite.py - builds the author_book_publisher.db database file
   
   
   

python-sqlite-sqlalchemy/project/build_data/build_author_book_publisher_sqlite.py

@@ -5,7 +5,7 @@ author_book_publisher.csv file.
 
 import os
 import csv
-from pkg_resources import resource_filename
+from importlib import resources
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 from project.modules.models import Base
@@ -30,11 +30,13 @@ def populate_database(session, author_book_publisher_data):
 
         author = (
             session.query(Author)
-            .filter(Author.lname == row["lname"])
+            .filter(Author.last_name == row["last_name"])
             .one_or_none()
         )
         if author is None:
-            author = Author(fname=row["fname"], lname=row["lname"])
+            author = Author(
+                first_name=row["first_name"], last_name=row["last_name"]
+            )
             session.add(author)
 
         book = (
@@ -69,19 +71,19 @@ def main():
     print("starting")
 
     # get the author/book/publisher data into a dictionary structure
-    csv_filepath = resource_filename(
+    with resources.path(
         "project.data", "author_book_publisher.csv"
-    )
-    author_book_publisher_data = get_author_book_publisher_data(csv_filepath)
+    ) as csv_filepath:
+        data = get_author_book_publisher_data(csv_filepath)
+        author_book_publisher_data = data
 
     # get the filepath to the database file
-    sqlite_filepath = resource_filename(
+    with resources.path(
         "project.data", "author_book_publisher.db"
-    )
-
-    # does the database exist?
-    if os.path.exists(sqlite_filepath):
-        os.remove(sqlite_filepath)
+    ) as sqlite_filepath:
+        # does the database exist?
+        if os.path.exists(sqlite_filepath):
+            os.remove(sqlite_filepath)
 
     # create the database
     engine = create_engine(f"sqlite:///{sqlite_filepath}")

python-sqlite-sqlalchemy/project/build_data/build_temp_data_csv.py

-import csv
-import datetime
-from random import randint
-from pkg_resources import resource_filename
-
-
-start_date = datetime.datetime.strptime("2019-01-02", "%Y-%m-%d")
-
-students = [
-    "John",
-    "Mary",
-    "Susan",
-    "Doug",
-    "Andrew",
-    "George",
-    "Martha",
-    "Paul",
-    "Helen",
-]
-
-temperature_data = [
-    10,
-    12,
-    16,
-    23,
-    13,
-    12,
-    14,
-    22,
-    25,
-    28,
-    32,
-    33,
-    37,
-    36,
-    35,
-    40,
-    44,
-    45,
-    50,
-    52,
-    58,
-    60,
-    66,
-    70,
-    70,
-    72,
-    78,
-    80,
-    81,
-    82,
-    85,
-    88,
-    90,
-    87,
-    90,
-    85,
-    82,
-    81,
-    78,
-    75,
-    72,
-    72,
-    70,
-    63,
-    65,
-    62,
-    60,
-    45,
-    40,
-    37,
-    30,
-    28,
-]
-
-
-def offset_temp(temperature):
-    """
-    This function modifies the temperature +/- a random
-    amount up to 10
-    :param temperature:     temperature to modify
-    :return:                modified temperature
-    """
-    return temperature + randint(-10, 10)
-
-
-def main():
-    # create the CSV file
-    csv_filepath = resource_filename("project.data", "temp_data.csv")
-
-    with open(csv_filepath, "w") as data_fh:
-
-        # create the writer
-        csv_writer = csv.writer(data_fh)
-
-        # write the header
-        header = ["name"]
-        for week in range(0, 52):
-            current_date = start_date + datetime.timedelta(days=week * 7)
-            header.append(current_date.strftime("%Y-%m-%d"))
-        csv_writer.writerow(header)
-
-        # iterate through the students and write their data
-        for student in students:
-            data = [student]
-            # iterate through the weeks
-            for week in range(0, 52):
-                data.append(offset_temp(temperature_data[week]))
-
-            csv_writer.writerow(data)
-
-
-if __name__ == "__main__":
-    main()

python-sqlite-sqlalchemy/project/build_data/build_temp_data_sqlite.py

-"""
-This program gathers information from the temp_data.db file about temperature
-"""
-
-import os
-import csv
-from pkg_resources import resource_filename
-from datetime import datetime
-from sqlalchemy import create_engine
-from sqlalchemy import Column, Integer, String, Date, Float
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy.ext.declarative import declarative_base
-
-
-Base = declarative_base()
-
-
-class TemperatureData(Base):
-    __tablename__ = "temperature_data"
-    temperature_data_id = Column(Integer, primary_key=True)
-    name = Column(String, nullable=False)
-    date = Column(Date, nullable=False)
-    value = Column(Float, nullable=False)
-
-
-def get_temperature_data(filepath):
-    """
-    This function gets the temperature data from the csv file
-    """
-    with open(filepath) as csvfile:
-        csv_reader = csv.DictReader(csvfile)
-        data = {row["name"]: row for row in csv_reader}
-        for value in data.values():
-            value.pop("name")
-        return data
-
-
-def populate_database(session, temperature_data):
-    # insert the data
-    for student, data in temperature_data.items():
-        for date, value in data.items():
-            temp_data = TemperatureData(
-                name=student,
-                date=datetime.strptime(date, "%Y-%m-%d").date(),
-                value=value,
-            )
-            session.add(temp_data)
-        session.commit()
-    session.close()
-
-
-def main():
-    print("starting")
-
-    # get the temperature data into a dictionary structure
-    csv_filepath = resource_filename("project.data", "temp_data.csv")
-    temperature_data = get_temperature_data(csv_filepath)
-
-    # get the filepath to the database file
-    sqlite_filepath = resource_filename("project.data", "temp_data.db")
-
-    # does the database exist?
-    if os.path.exists(sqlite_filepath):
-        os.remove(sqlite_filepath)
-
-    # create and populate the sqlite database
-    engine = create_engine(f"sqlite:///{sqlite_filepath}")
-    Base.metadata.create_all(engine)
-    Session = sessionmaker()
-    Session.configure(bind=engine)
-    session = Session()
-    populate_database(session, temperature_data)
-
-    print("finished")
-
-
-if __name__ == "__main__":
-    main()

python-sqlite-sqlalchemy/project/data/author_book_publisher.csv

-fname,lname,title,publisher
-Issac,Asimov,Foundation,Random House
+first_name,last_name,title,publisher
+Isaac,Asimov,Foundation,Random House
 Pearl,Buck,The Good Earth,Random House
 Pearl,Buck,The Good Earth,Simon & Schuster
 Tom,Clancy,The Hunt For Red October,Berkley
@@ -7,7 +7,7 @@ Tom,Clancy,Patriot Games,Simon & Schuster
 Stephen,King,It,Random House
 Stephen,King,It,Penguin Random House
 Stephen,King,Dead Zone,Random House
-Stephen,King,The Shinning,Penguin Random House
+Stephen,King,The Shining,Penguin Random House
 John,Le Carre,"Tinker, Tailor, Solider, Spy: A George Smiley Novel",Berkley
 Alex,Michaelides,The Silent Patient,Simon & Schuster
 Carol,Shaben,Into The Abyss,Simon & Schuster

python-sqlite-sqlalchemy/project/data/temp_data.csv

-name,2019-01-02,2019-01-09,2019-01-16,2019-01-23,2019-01-30,2019-02-06,2019-02-13,2019-02-20,2019-02-27,2019-03-06,2019-03-13,2019-03-20,2019-03-27,2019-04-03,2019-04-10,2019-04-17,2019-04-24,2019-05-01,2019-05-08,2019-05-15,2019-05-22,2019-05-29,2019-06-05,2019-06-12,2019-06-19,2019-06-26,2019-07-03,2019-07-10,2019-07-17,2019-07-24,2019-07-31,2019-08-07,2019-08-14,2019-08-21,2019-08-28,2019-09-04,2019-09-11,2019-09-18,2019-09-25,2019-10-02,2019-10-09,2019-10-16,2019-10-23,2019-10-30,2019-11-06,2019-11-13,2019-11-20,2019-11-27,2019-12-04,2019-12-11,2019-12-18,2019-12-25
-John,11,9,19,28,11,10,20,24,18,32,40,33,46,42,27,32,42,54,50,47,63,57,60,67,62,64,70,88,73,78,93,89,89,96,98,79,90,85,78,79,66,67,75,63,70,63,59,45,44,29,39,19
-Mary,20,21,25,32,14,11,11,20,31,22,24,33,28,32,43,50,37,51,42,48,56,67,76,67,66,74,88,86,91,86,85,88,100,84,82,78,73,76,84,82,70,73,77,71,70,58,56,53,40,41,39,31
-Susan,6,10,26,21,23,3,13,28,29,33,31,39,31,28,38,48,50,46,41,51,62,62,62,69,77,77,72,82,83,72,79,78,96,87,88,91,75,88,84,73,77,68,78,59,68,66,57,55,48,40,33,36
-Doug,3,11,11,26,8,4,18,27,25,21,42,24,35,28,42,38,52,39,60,62,55,59,72,74,63,65,75,82,83,73,84,92,82,93,100,90,92,73,68,71,62,65,62,64,66,68,56,46,31,35,39,19
-Andrew,12,21,8,17,12,16,23,12,19,32,27,42,34,44,35,47,45,54,55,60,56,56,62,71,72,62,72,80,85,86,91,98,80,88,84,92,89,88,71,78,63,79,68,67,62,57,54,44,39,30,36,23
-George,18,4,19,31,22,2,7,26,34,25,36,38,36,35,34,38,42,55,48,46,60,60,68,62,65,62,87,73,82,77,82,97,97,80,95,92,73,74,79,78,81,82,63,71,74,57,57,38,38,32,25,21
-Martha,14,12,6,20,10,12,7,26,32,25,41,31,30,38,42,37,50,47,56,51,58,70,74,63,70,76,73,89,77,82,77,80,88,81,81,77,89,73,87,74,77,72,62,61,57,67,56,46,40,32,25,34
-Paul,18,22,12,32,5,8,15,29,16,27,24,25,27,37,37,42,42,36,49,54,59,56,65,62,76,63,83,72,75,89,79,85,97,82,100,76,73,73,81,67,74,73,61,53,59,66,64,44,42,42,25,34
-Helen,14,6,13,18,20,11,12,16,31,19,34,41,44,46,39,50,39,38,50,48,51,61,56,73,78,73,73,90,86,90,82,97,100,90,92,80,73,79,72,82,62,76,72,72,68,56,69,52,41,40,37,36

python-sqlite-sqlalchemy/project/examples/example_1/README.md

-# Example 1
-
-This example uses the raw temp_data.csv file 
-to get data into the program and run
-various Python functions on it.
-
-In particular getting the average temperature
-for a date across all the samples, and getting the
-average temperature for every week for the entire
-year and returning it sorted.
\ No newline at end of file

python-sqlite-sqlalchemy/project/examples/example_1/main.py

 """
-This program gathers information from the temp_data.csv file about temperature
+This is the example 1 program file
+
+This example program was kindly created by Geir Arne Hjelle,
+another RealPython author, as part of the editorial process
+to improve this article and the information it presents.
+You can learn more about Geir from this URL:
+https://realpython.com/team/gahjelle/
 """
 
-import csv
-from pkg_resources import resource_filename
-from datetime import datetime
-from datetime import timedelta
-from typing import List, Dict
-from collections import defaultdict
+from importlib import resources
 
+import pandas as pd
+from treelib import Tree
 
-def get_temperature_data(filepath: str) -> Dict:
-    """
-    This function gets the temperature data from the csv file
-    """
-    with open(filepath) as csvfile:
-        csv_reader = csv.DictReader(csvfile)
-        data = {row["name"]: row for row in csv_reader}
-        for value in data.values():
-            value.pop("name")
-        return data
 
+def get_data(filepath):
+    """Get book data from the csv file"""
+    return pd.read_csv(filepath)
 
-def get_average_temp_by_date(
-    date_string: str, temperature_data: Dict
-) -> float:
-    """
-    This function gets the average temperature for all the samples
-    taken by the students by date
 
-    :param date_string:             date to find average temperature for
-    :param connection:              database connection
-    :return:                        average temp for date, or None if not found
-    """
-    # Target date
-    target_date = datetime.strptime(date_string, "%Y-%m-%d").date()
-
-    # Iterate through the data and get the data
-    data = []
-    for samples in temperature_data.values():
+def get_books_by_publisher(data, ascending=True):
+    """Returns the books by each publisher as a pandas series
 
-        # Iterate through the samples
-        for sample_date, sample in samples.items():
+    Args:
+        data: The pandas dataframe to get the from
+        ascending: The sorting direction for the returned data.
+        Defaults to True.
 
-            # Generate a date range for the sample
-            min_date = datetime.strptime(
-                sample_date, "%Y-%m-%d"
-            ).date() + timedelta(days=-3)
-            max_date = datetime.strptime(
-                sample_date, "%Y-%m-%d"
-            ).date() + timedelta(days=3)
-            if min_date <= target_date <= max_date:
-                data.append(float(sample))
+    Returns:
+        The sorted data as a pandas series
+    """
+    return data.groupby("publisher").size().sort_values(ascending=ascending)
 
-    # Get the average temp
-    return sum(data) / len(data)
 
+def get_authors_by_publisher(data, ascending=True):
+    """Returns the authors by each publisher as a pandas series
 
-def get_average_temp_sorted(direction: str, temperature_data: Dict) -> List:
-    dir = direction.lower()
-    if dir not in ["asc", "desc"]:
-        raise Exception(f"Unknown direction: {direction}")
+    Args:
+        data: The pandas dataframe to get the data from
+        ascending: The sorting direction for the returned data.
+        Defaults to True.
 
-    results = defaultdict(int)
-    for data in temperature_data.values():
-        for date, value in data.items():
-            results[date] += float(value)
+    Returns:
+        The sorted data as a pandas series
+    """
+    return (
+        data.assign(name=data.first_name.str.cat(data.last_name, sep=" "))
+        .groupby("publisher")
+        .nunique()
+        .loc[:, "name"]
+        .sort_values(ascending=ascending)
+    )
 
-    for date, total in results.items():
-        results[date] = float(total) / float(len(temperature_data.keys()))
 
-    # Convert dictionary to list
-    results = results.items()
+def add_new_book(data, author_name, book_title, publisher_name):
+    """Adds a new book to the system"""
 
-    # Sort the list in the appropriate order
-    return sorted(
-        results, key=lambda v: v[1], reverse=False if dir == "asc" else True
+    # Does the book exist?
+    first_name, _, last_name = author_name.partition(" ")
+    if any(
+        (data.first_name == first_name)
+        & (data.last_name == last_name)
+        & (data.title == book_title)
+        & (data.publisher == publisher_name)
+    ):
+        return data
+    # Add the new book
+    return data.append(
+        {
+            "first_name": first_name,
+            "last_name": last_name,
+            "title": book_title,
+            "publisher": publisher_name,
+        },
+        ignore_index=True,
     )
 
 
-def main():
-    print("starting")
+def output_author_hierarchy(data):
+    """Output the data as a hierarchy list of authors"""
+    authors = data.assign(
+        name=data.first_name.str.cat(data.last_name, sep=" ")
+    )
+    authors_tree = Tree()
+    authors_tree.create_node("Authors", "authors")
+    for author, books in authors.groupby("name"):
+        authors_tree.create_node(author, author, parent="authors")
+        for book, publishers in books.groupby("title")["publisher"]:
+            book_id = f"{author}:{book}"
+            authors_tree.create_node(book, book_id, parent=author)
+            for publisher in publishers:
+                authors_tree.create_node(publisher, parent=book_id)
 
-    # Get the temperature data into a dictionary structure
-    filepath = resource_filename("project.data", "temp_data.csv")
-    temperature_data = get_temperature_data(filepath)
+    # Output the hierarchical authors data
+    authors_tree.show()
 
-    # Get the average temperature by date
-    date_string = "2019-02-10"
-    average_temp = get_average_temp_by_date(date_string, temperature_data)
-    print(f"Average temp {date_string}: {average_temp:.2f}")
+
+def main():
+    """The main entry point of the program"""
+
+    # Get the resources for the program
+    with resources.path(
+        "project.data", "author_book_publisher.csv"
+    ) as filepath:
+        data = get_data(filepath)
+
+    # Get the number of books printed by each publisher
+    books_by_publisher = get_books_by_publisher(data, ascending=False)
+    for publisher, total_books in books_by_publisher.items():
+        print(f"Publisher: {publisher}, total books: {total_books}")
     print()
 
-    # Get the average temps for the year sorted ascending or descending
-    average_temps = get_average_temp_sorted("asc", temperature_data)
-    for date, average_temp in average_temps:
-        print(f"Date: {date}, average temp: {average_temp:.2f}")
+    # Get the number of authors each publisher publishes
+    authors_by_publisher = get_authors_by_publisher(data, ascending=False)
+    for publisher, total_authors in authors_by_publisher.items():
+        print(f"Publisher: {publisher}, total authors: {total_authors}")
     print()
 
-    print("finished")
+    # Output hierarchical authors data
+    output_author_hierarchy(data)
+
+    # Add a new book to the data structure
+    data = add_new_book(
+        data,
+        author_name="Stephen King",
+        book_title="The Stand",
+        publisher_name="Random House",
+    )
+    # Output the updated hierarchical authors data
+    output_author_hierarchy(data)
 
 
 if __name__ == "__main__":

python-sqlite-sqlalchemy/project/examples/example_2/README.md

-# Example 2
-
-This example uses temp_data.db database
-file to get data into the program and run
-various functions on it that use Sqlite SQL 
-to access the data.
-
-In particular getting the average temperature
-for a date across all the samples, and getting the
-average temperature for every week for the entire
-year and returning it sorted.
\ No newline at end of file

python-sqlite-sqlalchemy/project/examples/example_2/main.py

 """
-This program gathers information from the database file about temperature
+This program gathers information from the author_book_publisher.db
+SQLite database file
 """
 
-from pkg_resources import resource_filename
-from datetime import datetime
-from datetime import timedelta
-import sqlite3
+from importlib import resources
 
+from sqlalchemy import and_, create_engine
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.sql import asc, desc, func
 
-def get_average_temp_by_date(date_string, connection):
-    """
-    This function gets the average temperature for all the samples
-    taken by the students by date
+from project.modules.models import Author, Book, Publisher
+from treelib import Tree
 
-    :param date_string:             date to find average temperature for
-    :param connection:              database connection
-    :return:                        average temp for date, or None if not found
-    """
-    # Target date
-    target_date = datetime.strptime(date_string, "%Y-%m-%d").date()
-    min_date = target_date + timedelta(days=-3)
-    max_date = target_date + timedelta(days=3)
-
-    cursor = connection.cursor()
-    sql = """
-        SELECT
-          avg(value) as average
-        FROM temperature_data
-        WHERE date between ? and ?
+
+def get_books_by_publishers(session, ascending=True):
+    """Get a list of publishers and the number of books they've published
+
+    Args:
+        session: database session to use
+        ascending: direction to sort the results
+
+    Returns:
+        List: list of publisher sorted by number of books published
     """
-    result = cursor.execute(sql, (min_date, max_date)).fetchone()
-    return result[0] if result else None
+    if not isinstance(ascending, bool):
+        raise ValueError(f"Sorting value invalid: {ascending}")
 
+    direction = asc if ascending else desc
 
-def get_average_temp_sorted(direction: str, connection) -> list:
+    return (
+        session.query(
+            Publisher.name, func.count(Book.title).label("total_books")
+        )
+        .join(Publisher.books)
+        .group_by(Publisher.name)
+        .order_by(direction("total_books"))
+    )
 
-    dir = direction.lower()
-    if dir not in ["asc", "desc"]:
-        raise Exception(f"Unknown direction: {direction}")
 
-    cursor = connection.cursor()
-    sql = f"""
-        SELECT
-            date,
-            AVG(value) as average_temp
-        FROM temperature_data
-        GROUP BY date
-        ORDER BY average_temp {dir}
-    """
-    results = cursor.execute(sql).fetchall()
-    return results
+def get_authors_by_publishers(session, ascending=True):
+    """Get a list of publishers and the number of authors they've published
 
+    Args:
+        session: database session to use
+        ascending: direction to sort the results
 
-def main():
-    print("starting")
+    Returns:
+        List: list of publisher sorted by number of authors published
+    """
+    if not isinstance(ascending, bool):
+        raise ValueError(f"Sorting value invalid: {ascending}")
+
+    direction = asc if ascending else desc
+
+    return (
+        session.query(
+            Publisher.name,
+            func.count(Author.first_name).label("total_authors"),
+        )
+        .join(Publisher.authors)
+        .group_by(Publisher.name)
+        .order_by(direction("total_authors"))
+    )
+
+
+def get_authors(session):
+    """Get a list of author objects sorted by last name"""
+    return session.query(Author).order_by(Author.last_name).all()
+
+
+def add_new_book(session, author_name, book_title, publisher_name):
+    """Adds a new book to the system"""
+
+    # Get the author's first and last names
+    first_name, _, last_name = author_name.partition(" ")
+
+    # Check if the book exists
+    book = (
+        session.query(Book)
+        .join(Author)
+        .filter(Book.title == book_title)
+        .filter(
+            and_(
+                Author.first_name == first_name, Author.last_name == last_name
+            )
+        )
+        .filter(Book.publishers.any(Publisher.name == publisher_name))
+        .one_or_none()
+    )
+    # Does the book by the author and publisher already exist?
+    if book is not None:
+        return
+
+    # Check if the book exists for the author
+    book = (
+        session.query(Book)
+        .join(Author)
+        .filter(Book.title == book_title)
+        .filter(
+            and_(
+                Author.first_name == first_name, Author.last_name == last_name
+            )
+        )
+        .one_or_none()
+    )
+    # Create the new book if needed
+    if book is None:
+        book = Book(title=book_title)
+
+    # Get the author
+    author = (
+        session.query(Author)
+        .filter(
+            and_(
+                Author.first_name == first_name, Author.last_name == last_name
+            )
+        )
+        .one_or_none()
+    )
+    # Do we need to create the author?
+    if author is None:
+        author = Author(first_name=first_name, last_name=last_name)
+        session.add(author)
+
+    # Get the publisher
+    publisher = (
+        session.query(Publisher)
+        .filter(Publisher.name == publisher_name)
+        .one_or_none()
+    )
+    # Do we need to create the publisher?
+    if publisher is None:
+        publisher = Publisher(name=publisher_name)
+        session.add(publisher)
+
+    # Initialize the book relationships
+    book.author = author
+    book.publishers.append(publisher)
+    session.add(book)
+
+    # Commit to the database
+    session.commit()
+
+
+def output_author_hierarchy(authors):
+    """
+    Outputs the author/book/publisher information in
+    a hierarchical manner
+
+    :param authors:         the collection of root author objects
+    :return:                None
+    """
+    authors_tree = Tree()
+    authors_tree.create_node("Authors", "authors")
+    for author in authors:
+        author_id = f"{author.first_name} {author.last_name}"
+        authors_tree.create_node(author_id, author_id, parent="authors")
+        for book in author.books:
+            book_id = f"{author_id}:{book.title}"
+            authors_tree.create_node(book.title, book_id, parent=author_id)
+            for publisher in book.publishers:
+                authors_tree.create_node(publisher.name, parent=book_id)
+    # Output the hierarchical authors data
+    authors_tree.show()
 
-    # Connect to the sqlite database
-    sqlite_filepath = resource_filename("project.data", "temp_data.db")
-    connection = sqlite3.connect(sqlite_filepath)
 
-    # Get the average temperature by date
-    date_string = "2019-02-10"
-    average_temp = get_average_temp_by_date(date_string, connection)
-    print(f"Average temp {date_string}: {average_temp:.2f}")
+def main():
+    """Main entry point of program"""
+
+    # Connect to the database using SQLAlchemy
+    with resources.path(
+        "project.data", "author_book_publisher.db"
+    ) as sqlite_filepath:
+        engine = create_engine(f"sqlite:///{sqlite_filepath}")
+    Session = sessionmaker()
+    Session.configure(bind=engine)
+    session = Session()
+
+    # Get the number of books printed by each publisher
+    books_by_publisher = get_books_by_publishers(session, ascending=False)
+    for row in books_by_publisher:
+        print(f"Publisher: {row.name}, total books: {row.total_books}")
     print()
 
-    # Get the average temps for the year sorted ascending or descending
-    average_temps = get_average_temp_sorted("asc", connection)
-    for date, average_temp in average_temps:
-        print(f"Date: {date}, average temp: {average_temp:.2f}")
+    # Get the number of authors each publisher publishes
+    authors_by_publisher = get_authors_by_publishers(session)
+    for row in authors_by_publisher:
+        print(f"Publisher: {row.name}, total authors: {row.total_authors}")
     print()
 
-    print("finished")
+    # Output hierarchical authors data
+    authors = get_authors(session)
+    output_author_hierarchy(authors)
+
+    # Add a new book
+    add_new_book(
+        session,
+        author_name="Stephen King",
+        book_title="The Stand",
+        publisher_name="Random House",
+    )
+    # Output the updated hierarchical authors data
+    authors = get_authors(session)
+    output_author_hierarchy(authors)
 
 
 if __name__ == "__main__":

python-sqlite-sqlalchemy/project/examples/example_3/README.md

-# Example 3
-
-This example uses SqlAlchemy to access the temp_data.db 
-database to get data into the program and run
-various SqlAlchemy object methods to get the data.
-
-In particular getting the average temperature
-for a date across all the samples, and getting a list 
-of all the average temps for the year in sorted order.
\ No newline at end of file

python-sqlite-sqlalchemy/project/examples/example_3/app/__init__.py

+from flask import Flask
+from flask import render_template
+from flask_bootstrap import Bootstrap
+from flask_sqlalchemy import SQLAlchemy
+from config import Config
+
+# Define the application
+app = Flask(__name__, instance_relative_config=False)
+
+# Configure the application
+app.config.from_object(Config)
+
+# Define the database object
+db = SQLAlchemy(app)
+
+# Initialize Bootstrap connection
+Bootstrap(app)
+
+# Register Blueprings
+from .artists import routes as artist_routes  # noqa: E402
+from .albums import routes as album_routes  # noqa: E402
+from .tracks import routes as track_routes  # noqa: E402
+from .playlists import routes as playlist_routes  # noqa: E402
+from .customers import routes as customer_routes  # noqa: E402
+from .invoices import routes as invoice_routes  # noqa: E402
+from .employees import routes as employee_routes  # noqa: E402
+
+app.register_blueprint(artist_routes.artists_bp)
+app.register_blueprint(album_routes.albums_bp)
+app.register_blueprint(track_routes.tracks_bp)
+app.register_blueprint(playlist_routes.playlists_bp)
+app.register_blueprint(customer_routes.customers_bp)
+app.register_blueprint(invoice_routes.invoices_bp)
+app.register_blueprint(employee_routes.employees_bp)
+
+
+# Sample HTTP error handling
+@app.errorhandler(404)
+def not_found(error):
+    return render_template("404.html"), 404
+
+
+from app import models  # noqa: F401, E402

python-sqlite-sqlalchemy/project/examples/example_3/app/albums/routes.py

+from flask import Blueprint, render_template, redirect, url_for
+from flask_wtf import FlaskForm
+from wtforms import StringField
+from wtforms import HiddenField
+from wtforms.validators import InputRequired, ValidationError
+from app import db
+from app.models import Artist, Album
+
+
+# Setup the Blueprint
+albums_bp = Blueprint(
+    "albums_bp", __name__, template_folder="templates", static_folder="static"
+)
+
+
+def does_album_exist(form, field):
+    album = (
+        db.session.query(Album)
+        .join(Artist)
+        .filter(Artist.name == form.artist.data)
+        .filter(Album.title == field.data)
+        .one_or_none()
+    )
+
+    if album is not None:
+        raise ValidationError("Album already exists", field.data)
+
+
+class CreateAlbumForm(FlaskForm):
+    artist = HiddenField("artist")
+    title = StringField(
+        label="Albums's Name", validators=[InputRequired(), does_album_exist]
+    )
+
+
+@albums_bp.route("/albums", methods=["GET", "POST"])
+@albums_bp.route("/albums/<int:artist_id>", methods=["GET", "POST"])
+def albums(artist_id=None):
+    form = CreateAlbumForm()
+
+    # did we get an artist id?
+    if artist_id is not None:
+        # Get the artist
+        artist = (
+            db.session.query(Artist)
+            .filter(Artist.artist_id == artist_id)
+            .one_or_none()
+        )
+        form.artist.data = artist.name
+    # otherwise, no artist
+    else:
+        artist = None
+
+    # Is the form valid?
+    if form.validate_on_submit():
+        # Create new Album
+        album = Album(title=form.title.data)
+        artist.albums.append(album)
+        db.session.add(artist)
+        db.session.commit()
+        return redirect(url_for("albums_bp.albums", artist_id=artist_id))
+
+    # Start the query for albums
+    query = db.session.query(Album)
+
+    # Display the albums for the artist passed?
+    if artist_id is not None:
+        query = query.filter(Album.artist_id == artist_id)
+
+    albums = query.order_by(Album.title).all()
+
+    return render_template(
+        "albums.html", artist=artist, albums=albums, form=form
+    )

python-sqlite-sqlalchemy/project/examples/example_3/app/albums/templates/albums.html

+{% extends "base.html" %}
+
+
+{% block content %}
+<div class="container-fluid">
+  <div class="m-4">
+    {% if artist is not none %}
+    <div class="card" style="width: 18rem;">
+      <div class="card-header">Create New Album</div>
+      <div class="card-body">
+        <p class="card-text">Artist Name:&nbsp;{{ artist.name }}</p>
+        <form method="POST" action="{{url_for('albums_bp.albums', artist_id=artist.artist_id)}}">
+          {{ form.csrf_token }}
+          {{ render_field(form.title, placeholder=form.title.label.text) }}
+          <button type="submit" class="btn btn-primary">Create</button>
+        </form>
+      </div>
+    </div>
+    {% endif %}
+    <table class="table table-striped table-bordered table-hover table-sm">
+      <caption>List of Albums</caption>
+      <thead>
+        <tr>
+          <th>Album Name</th>
+        </tr>
+      </thead>
+      <tbody>
+        {% for album in albums %}
+        <tr>
+          <td>
+            <a href="{{url_for('tracks_bp.tracks', album_id=album.album_id)}}">
+              {{ album.title }}
+            </a>
+          </td>
+        </tr>
+        {% endfor %}
+      </tbody>
+    </table>
+  </div>
+</div>
+{% endblock %}
\ No newline at end of file

python-sqlite-sqlalchemy/project/examples/example_3/app/artists/routes.py

+from flask import Blueprint
+from flask import render_template
+from flask import redirect
+from flask import url_for
+from flask_wtf import FlaskForm
+from wtforms import StringField
+from wtforms.validators import InputRequired
+from wtforms.validators import ValidationError
+from app import db
+from app.models import Artist
+
+
+# Setup the Blueprint
+artists_bp = Blueprint(
+    "artists_bp", __name__, template_folder="templates", static_folder="static"
+)
+
+
+def does_artist_exist(form, field):
+    artist = (
+        db.session.query(Artist)
+        .filter(Artist.name == field.data)
+        .one_or_none()
+    )
+    if artist is not None:
+        raise ValidationError("Artist already exists", field.data)
+
+
+class CreateArtistForm(FlaskForm):
+    name = StringField(
+        label="Artist's Name", validators=[InputRequired(), does_artist_exist]
+    )
+
+
+@artists_bp.route("/")
+@artists_bp.route("/artists", methods=["GET", "POST"])
+def artists():
+    form = CreateArtistForm()
+
+    # Is the form valid?
+    if form.validate_on_submit():
+        # Create new artist
+        artist = Artist(name=form.name.data)
+        db.session.add(artist)
+        db.session.commit()
+        return redirect(url_for("artists_bp.artists"))
+
+    artists = db.session.query(Artist).order_by(Artist.name).all()
+    return render_template("artists.html", artists=artists, form=form)

python-sqlite-sqlalchemy/project/examples/example_3/app/artists/templates/artists.html

+{% extends "base.html" %}
+
+{% block content %}
+<div class="container-fluid">
+  <div class="m-4">
+    <div class="card" style="width: 18rem;">
+      <div class="card-header">Create New Artist</div>
+      <div class="card-body">
+        <form method="POST" action="{{url_for('artists_bp.artists')}}">
+          {{ form.csrf_token }}
+          {{ render_field(form.name, placeholder=form.name.label.text) }}
+          <button type="submit" class="btn btn-primary">Create</button>
+        </form>
+      </div>
+    </div>
+    <table class="table table-striped table-bordered table-hover table-sm">
+      <caption>List of Artists</caption>
+      <thead>
+        <tr>
+          <th>Artist Name</th>
+        </tr>
+      </thead>
+      <tbody>
+        {% for artist in artists %}
+        <tr>
+          <td>
+            <a href="{{url_for('albums_bp.albums', artist_id=artist.artist_id)}}">
+              {{ artist.name }}
+            </a>
+          </td>
+        </tr>
+        {% endfor %}
+      </tbody>
+    </table>
+  </div>
+</div>
+{% endblock %}
\ No newline at end of file

python-sqlite-sqlalchemy/project/examples/example_3/app/customers/routes.py

+from flask import Blueprint
+from flask import render_template
+from sqlalchemy import func
+from app import db
+from app.models import Customer
+from app.models import Invoice
+from sqlalchemy import desc
+
+
+# Setup the Blueprint
+customers_bp = Blueprint(
+    "customers_bp",
+    __name__,
+    template_folder="templates",
+    static_folder="static",
+)
+
+
+@customers_bp.route("/customers", methods=["GET"])
+@customers_bp.route("/customers/<int:customer_id>", methods=["GET"])
+def customers(customer_id=None):
+
+    # Start the query for customers
+    query = db.session.query(
+        Customer, func.sum(Invoice.total).label("invoices_total")
+    ).join(Invoice)
+
+    # Display the albums for the customer passed?
+    if customer_id is not None:
+        query = query.filter(Customer.customer_id == customer_id)
+
+    results = (
+        query.group_by(Customer.customer_id)
+        .order_by(desc(func.sum(Invoice.total)))
+        .all()
+    )
+    return render_template("customers.html", results=results)

python-sqlite-sqlalchemy/project/examples/example_3/app/employees/routes.py

+from flask import Blueprint
+from flask import render_template
+from app import db
+from app.models import Employee
+
+
+# Setup the Blueprint
+employees_bp = Blueprint(
+    "employees_bp",
+    __name__,
+    template_folder="templates",
+    static_folder="static",
+)
+
+
+@employees_bp.route("/employees", methods=["GET"])
+@employees_bp.route("/employees/<int:employee_id>", methods=["GET"])
+def employees(employee_id=None):
+
+    # Start the query for employees
+    query = db.session.query(Employee)
+
+    # Display the employee for the employee id passed?
+    if employee_id is not None:
+        query = query.filter(Employee.employee_id == employee_id)
+
+    employees = query.order_by(Employee.employee_id).all()
+
+    return render_template("employees.html", employees=employees)

python-sqlite-sqlalchemy/project/examples/example_3/app/invoices/routes.py

+from flask import Blueprint
+from flask import render_template
+from app import db
+from app.models import Invoice
+
+
+# Setup the Blueprint
+invoices_bp = Blueprint(
+    "invoices_bp",
+    __name__,
+    template_folder="templates",
+    static_folder="static",
+)
+
+
+@invoices_bp.route("/invoices", methods=["GET"])
+@invoices_bp.route("/invoices/<int:invoice_id>", methods=["GET"])
+def invoices(invoice_id=None):
+    # Start the query for invoices
+    query = db.session.query(Invoice)
+
+    # Display the invoice for the invoice id passed?
+    if invoice_id is not None:
+        query = query.filter(Invoice.invoice_id == invoice_id)
+
+    invoices = query.order_by(Invoice.invoice_id).all()
+    return render_template("invoices.html", invoices=invoices)