varmap1={'aa':'aaa','bb':'bbb','cc':true};//直接赋值初始值print(map1);//{aa: aaa, bb: bbb, cc: true}Map map2={'a':'a1','b':'b1'};//直接赋值初始值print(map2);//{a: a1, b: b1}map2['c']='c1';print(map2);//{a: a1, b: b1, c: c1}varmap3=newMap();...
Map<String,String> map1 = {'a':'dart','b':'java'}; map1.putIfAbsent('c',()=>'C++'); putIfAbsent 用法: /** * Look up the value of [key], or add a new value if it isn't there. * * Returns the value associated to [key], if there is one. * Otherwise calls [ifAbsent...
Map<String,int> map6 = {"a":1,"b":2};// print(map6.length);//2 长度// print(map6.isNotEmpty);//true 是否不为空// print(map6.isEmpty);//false 是否为空// print(map6.keys);//(a, b) key的集合// print(map6.values);//(1, 2) value的集合// print(map6.entries);//...
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/falseforEach mapwhereany every voidmain(){// Map person={// "name":"张三",// "age":20// }...
Map map=newMap();map['name']='zhangsan';map['name2']='zhangsan2';map.forEach((key,value){print('key = $key , value = $value');}); image.png 2,map 方法: 用于修改原集合数据 例如: List<String>stringList=List<String>();stringList.add('old1');stringList.add('old2');print(...
map4[2]="b"; // print(map4);//{1: a, 2: b} Map<String,int>map5={"a":1,"b":2}; // print(map5);//{a: 1, b: 2} 1. 2. 3. 4. 5. 6. 7. 属性 Map<String,int>map6={"a":1,"b":2}; // print(map6.length);//2 长度 ...
Map testMap = {'a':1, 'b':2, 'c':3}; print(testMap.values.toList()); // [1, 2, 3] isEmpty/isNotEmpty Map 是否为空,return bool。 addAll 代码语言:javascript 复制 Map testMap = {'a':1, 'b':2, 'c':3}; testMap.addAll({'a':100, 'd':99}); print(testMap); /...
Map<String ,int> map14 = {'a14':1}; bool resultMap14 = map14.containsKey('a11'); //false bool resultMap141 = map14.containsValue(1); //true forEach(void f(K key, V value)) 遍历Map ,遍历时不可add或者remove 代码语言:javascript 复制 Map<String, int> map15 = {'a15': 1, 'b15...
本文主要介绍dart语言基础Map ” Map定义 不指定泛型 var map1 = {'aa':'aaa','bb':'bbb','cc':true}; //直接赋值初始值 print(map1); //{aa: aaa, bb: bbb, cc:true} Map map2 = {'a':'a1','b':'b1'}; //直接赋值初始值 ...
Map是一个key-value键值对的集合对象,其key和value是一对多的关系;类似于Android中Map,Dart Map也分为HashMap无序的Map集合、LinkedHashMap插入有序的Map集合以及SplayTreeMap已排序好的Map集合;主要在dart.core核心库中; Map与List都属于泛型类,其中key-value均不指定具体类型,默认为dynamic; ...