JS中对List、Map的各种遍历方式
var list1 = ["number","name"];
var list2 = ["36","Crown","15","Faker","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]); }
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
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版权声明:本文为CSDN博主「98年的香奈儿」的原创文章,遵循CC 4.0 BY-SA版权协议,转载请附上原文出处链接及本声明。
原文链接:https://blog.csdn.net/soicant/article/details/79318181