1、forEach遍历:
map.forEach(function(value,key){
console.log(value,key);
});
函数中第一个参数是属性值,第二个参数是属性
2、for-of遍历:ES6新语法
①for(let item of map){
}
遍历结果是数组
②for(let item of map.values()){
}
遍历属性值
③for(let item of map.keys()){
}
遍历属性
3、entries遍历:
for(let item of map.entries()){
}
var list1 = [“number”,”name”];
var list2 = [“36″,”Crown”,”15″,”高大的乌龟”,”Swift”,”68″,”Dandy”];
var map_demo = { name: “John”, lang: “JS” };
1.最常用的for循环
for(var i=0;i<list2.length;i++){
console.info(i +”:”+ list2 [i]);
}
改进:这里可以将list2.length提出来,不用每次计算长度,效率更高一些,such as:
var len=list2.length;
for(var i=0;i<len;i++){
console.info(i +”:”+ list2 [i]);
}
小结:很常见也很常用,效率也不差,但不能遍历map。
2.for…in…遍历List/map
//遍历map
for(var key in map_demo){
console.info(key+”:”+map_demo[key]);
}
//遍历List
for(var index in list2){
console.info(index+”:”+list2[index]);
}
小结:对于List来说,能不用for…in就不要用,效率低下。
3.forEach遍历List
list2.forEach(function (element, index, array) {
console.info(element); //当前元素的值
console.info(index); //当前下标
console.info(array); //数组本身
});
小结:和for循环效率差不多。
4.$.each()遍历List/map
//遍历List
$.each(list2,function(index,items){
console.info(index+”:”+items);
});
//遍历map
$.each(map_demo,function(key,value){
console.info(“key: ” + key + “, Value: ” + value );
})
5.$.map()遍历List/map
//遍历List
var new_list = $.map(list2,function(items,index){
return items+”!”;
})
console.info(new_list);
//遍历map
$.map(map_demo,function(key,value){
console.log(key+”:”+value);
});
小结:$.map()写法和$.each()类似,但对list的遍历时,参数顺序和$.each()是相反的,并且可以带返回值。对map的遍历和$.each()一样
var businessHtml = ‘<dt>业务类系统:</dt>’;
var businessMap = data.system[“1”];
for (var key in businessMap) {
businessHtml += ‘<dd οnclick=”elementSystemChange(this,’+ key +’)”>’+businessMap[key]+'</dd>’
}<快三稳赚10大技巧ems){
console.info(index+”:”+items);
});
//遍历map
$.each(map_demo,function(key,value){
console.info(“key: ” + key + “, Value: ” + value );
})
5.$.map()遍历List/map
//遍历List
var new_list = $.map(list2,function(items,index){
return items+”!”;
})
console.info(new_list);
//遍历map
$.map(map_demo,function(key,value){
console.log(key+”:”+value);
});
小结:$.map()写法和$.each()类似,但对list的遍历时,参数顺序和$.each()是相反的,并且可以带返回值。对map的遍历和$.each()一样
var businessHtml = ‘<dt>业务类系统:</dt>’;
var businessMap = data.system[“1”];
for (var key in businessMap) {
businessHtml += ‘<dd οnclick=”elementSystemChange(this,’+ key +’)”>’+businessMap[key]+'</dd>’
}
$(‘#businessList’).html(businessHtml);