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映射(Maps)是无序的键值对：
常用属性：
keys 获取所有的key值
values 获取所有的value值
isEmpty 是否为空
isNotEmpty 是否不为空
常用方法:
remove(key) 删除指定key的数据
addAll({...}) 合并映射 给映射内增加属性
containsValue 查看映射内的值 返回true/false
forEach
map
where
any
every
创建Map: var map1 = {"first":"Dart",1:true,true:"2"};
创建不可变Map: var map2 = const{"first":"Dart",1:true,true:"2"};
常用操作[],length,keys,values, containsKey, containsValue, remove,forEach var map1 = {"first":"Dart",1:true,true:"2"}; print(map1); print(map1["first"]); print(map1[true]); map1[1] = false; print(map1); var map2 = const {1:"Dart",2:"Java"}; // map2[1] = "Python"; //Unsupported operation: Cannot set value in unmodifiable Map var map3 = new Map(); print(map3); var map = {"first":"Dart","second":"Java","third":"Python"}; print(map.length); // map.isEmpty; print(map.keys); print(map.values); print(map.containsKey("first")); print(map.containsValue("C")); map.remove("third"); print(map); map.forEach(f); var list = ["1","2","3"]; print(list.asMap()); 输出： {first: Dart, 1: true, true: 2}
Dart
2
{first: Dart, 1: false, true: 2}
{}
3
(first, second, third)
(Dart, Java, Python)
true
false
{first: Dart, second: Java}
key=first,value=Dart
key=second,value=Java
{0: 1, 1: 2, 2: 3}
Dart学习系列文章：https://www.cnblogs.com/jukaiit/category/1636484.html |
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