文章目录
一、Array.forEach() 遍历
没有返回值
var a = [20,30,40]
a.forEach(function(value,key,arr){
console.log(value+","+key+",["+arr+"]")
})
//"20,0,[20,30,40]"
//"30,1,[20,30,40]"
//"40,2,[20,30,40]"
二、Array.sort() 排序
var a = [1,3,6,9,2,7];
a.sort(function(x,y){return x-y}) //[1, 2, 3, 6, 7, 9]
a.sort(function(x,y){return y-x}) //[9, 7, 6, 3, 2, 1]
三、Array.filter 过滤
var a = [1,2,3,4,5,6]
a.filter(function(x){return x > 3}) //[4,5,6]
四、Array.join 以什么作为间隔合并成字符串
var a = [1,2,3]
a.join("--") //"1--2--3"
五、Array.concat 合并数组
var a = [1,2,3],b=[4,5,6,7]
a.concat(b) //[1,2,3,4,5,6,7]
六、Array.map 返回一个处理后的数组
var a = [1,2,3]
a.map(function(x){return x*2}) //[2,4,6]
七、Array.reduce
var a = [1,2,3]
//可替代map
a.reduce(function(arr,n){
arr.push(n*2);
return arr
},[])
//[2,4,6]
a.reduce(function(a,b){
return a+b
})
//6