update README.md

itertools-in-python3/README.md

-# Itertools In Python 3, By Example
+# Itertools in Python 3, By Example
 
-> Supplemental materials for the [Itertools In Python 3, By Example](https://realpython.com/itertools-in-python3) article on [Real Python](https://realpython.com).
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+> Supplemental materials for the [Itertools in Python 3, By Example](https://realpython.com/itertools-in-python3) article on [Real Python](https://realpython.com).
+
+This folder contains content for two example from the article: [Analyzing the S&P500](https://realpython.com/python3-itertools/#analyzing-the-sp500) and [Building Relay Teams from Swimmer Data](https://realpython.com/python3-itertools/#building-relay-teams-from-swimmer-data).
+
+## Downloading the Files
+
+### With `git`
+
+If you have `git` installed, the easiest way to access these files is to clone the repository to the directory of your choice:
+
+```console
+git clone https://github.com/realpython/materials.git
+```
+
+Then `cd` into the `itertools-in-python3` directory:
+
+```console
+cd itertools-in-python3
+```
+
+### Without `git`
+
+Alternatively, you can download the entire repository as a `.zip` file from the repository's [homepage](https://github.com/realpython/materials) using the green "Clone or download" button in the top right hand corner.
+
+![Download repo as zip](download-zip.gif)
+
+## Running the Code Examples
+
+To run the code examples, first make sure you have Python 3 installed on your machine. **The code examples WILL NOT work with Python 2.** If you need help installing Python 3, check out Real Python's [Python 3 Installation & Setup Guide](https://realpython.com/installing-python/).
+
+To run the `sp500.py` file, type `python3 sp500.py` into your terminal. Here's how that looks, with output:
+
+```console
+$ python3 sp500.py
+Max gain: 11.58% on 2008-10-13
+Max loss: -20.47% on 1987-10-19
+Longest growth streak: 14 days (1971-03-26 to 1971-04-15)
+```
+
+Similarly, for `swimmers.py`:
+
+```console
+$ python3 swimmers.py
+Backstroke A: Sophia, Grace, Penelope, Addison
+Backstroke B: Elizabeth, Audrey, Emily, Aria
+Breaststroke A: Samantha, Avery, Layla, Zoe
+Breaststroke B: Lillian, Aria, Ava, Alexa
+Butterfly A: Audrey, Leah, Layla, Samantha
+Butterfly B: Alexa, Zoey, Emma, Madison
+Freestyle A: Aubrey, Emma, Olivia, Evelyn
+Freestyle B: Elizabeth, Zoe, Addison, Madison
+```
+
+> **Note:** Depending on your installation, you may need to type `python3.6` or `python36` to run the examples. If you follow the [Python 3 Installation & Setup Guide](https://realpython.com/installing-python/), you should have no problem.
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