From 19a92fe9d3ff9e5353ac77741ac1ae22038d8fd8 Mon Sep 17 00:00:00 2001 From: Mars Liu Date: Mon, 15 Nov 2021 12:22:49 +0800 Subject: [PATCH] exerices --- .../config.json" | 3 +- .../to_list.json" | 6 +++ .../to_list.md" | 35 +++++++++++++++++ .../to_set.json" | 6 +++ .../to_set.md" | 39 +++++++++++++++++++ 5 files changed, 87 insertions(+), 2 deletions(-) create mode 100644 "data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_list.json" create mode 100644 "data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_list.md" create mode 100644 "data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_set.json" create mode 100644 "data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_set.md" diff --git "a/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/config.json" "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/config.json" index 015f92d..6edd4d8 100644 --- "a/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/config.json" +++ "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/config.json" @@ -2,6 +2,5 @@ "node_id": "java-0f1fc49b2e1c41368403ca2239810920", "keywords": [], "children": [], - "export": [], - "title": "收集器简介" + "export": ["to_list.json"] } \ No newline at end of file diff --git "a/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_list.json" "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_list.json" new file mode 100644 index 0000000..53268b0 --- /dev/null +++ "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_list.json" @@ -0,0 +1,6 @@ +{ + "type": "code_options", + "author": "刘鑫", + "source": "to_list.md", + "notebook_enable": false +} \ No newline at end of file diff --git "a/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_list.md" "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_list.md" new file mode 100644 index 0000000..924b06d --- /dev/null +++ "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_list.md" @@ -0,0 +1,35 @@ +# Stream To List + +下面的选项尝试从一个整数 Stream 对象中构造 List。那么不正确的是： + +## 答案 + +```java +return new ArrayList<>(stream); +``` + +## 选项 + +### 推荐做法 + +```java +return stream.collect(Collectors.toList()); +``` + +### 朴素做法，不推荐但可用 + +```java +List result = new ArrayList<>(); +stream.foreach(x -> { + result.add(x); +}); +return result; +``` + +### 方法引用 + +```java +List result = new ArrayList<>(); +stream.foreach(result::add); +``` + diff --git "a/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_set.json" "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_set.json" new file mode 100644 index 0000000..e53c216 --- /dev/null +++ "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_set.json" @@ -0,0 +1,6 @@ +{ + "type": "code_options", + "author": "刘鑫", + "source": "to_set.md", + "notebook_enable": false +} \ No newline at end of file diff --git "a/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_set.md" "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_set.md" new file mode 100644 index 0000000..abab247 --- /dev/null +++ "b/data/3.Java\351\253\230\351\230\266/4.\346\224\266\351\233\206\345\231\250/to_set.md" @@ -0,0 +1,39 @@ +# Stream To Set + +下面的选项尝试从一个整数 Stream 对象中构造 List。那么不正确的是： + +## 答案 + +```java +return new HashSet<>(stream); +``` + +## 选项 + +### 推荐做法 + +```java +return stream.collect(Collectors.toSet()); +``` + +### 朴素做法，不推荐但可用 + +```java +List result = new ArrayList<>(); + stream.foreach(x -> { + result.add(x); + }); + return result; +``` + +### 方法引用 + +```java +Set result = new HashSet<>(); +stream.foreach(result::add); +``` + + + + + -- GitLab