JavaScript数组复制详解

前面的话
前面的博文中介绍了对象拷贝，本文将详细介绍数组复制
push

function copyArray（arr）{var result = [];for（var i = 0; i < arr.length; i++）{result.push（arr[i]）;}return result;}var obj1=[1,2,3];var obj2=copyArray（obj1）;console.log（obj1）; //[1,2,3]console.log（obj2）; //[1,2,3]obj2.push（4）;console.log（obj1）; //[1,2,3]console.log（obj2）; //[1,2,3,4]

join
使用该方法的缺点是数组中的项全部变成了字符串形式

function copyArray（arr）{var result = [];result = arr.join（）.split（","）;return result;}var obj1=[1,2,3];var obj2=copyArray（obj1）;console.log（obj1）; //[1,2,3]console.log（obj2）; //["1","2","3"]obj2.push（4）;console.log（obj1）; //[1,2,3]console.log（obj2）; //["1","2","3",4]

concat

function copyArray（arr）{var result = [];result = arr.concat（）;return result;}var obj1=[1,2,3];var obj2=copyArray（obj1）;console.log（obj1）; //[1,2,3]console.log（obj2）; //[1,2,3]obj2.push（4）;console.log（obj1）; //[1,2,3]console.log（obj2）; //[1,2,3,4]

slice

function copyArray（arr）{var result = [];result = arr.slice（）;return result;}var obj1=[1,2,3];var obj2=copyArray（obj1）;console.log（obj1）; //[1,2,3]console.log（obj2）; //[1,2,3]obj2.push（4）;console.log（obj1）; //[1,2,3]console.log（obj2）; //[1,2,3,4]

深拷贝
以上方法实现的仅是数组的浅拷贝，如果要实现数组的深拷贝，需要使用递归方法

function copyArray（arr,result）{var result = result || [];for（var i = 0; i < arr.length; i++）{if（arr[i] instanceof Array）{result[i] = [];copyArray（arr[i],result[i]）;}else{result[i] = arr[i];}}return result;}var obj1=[1,2,[3,4]];var obj2=copyArray（obj1）;console.log（obj1[2]）; //[3,4]console.log（obj2[2]）; //[3,4]obj2[2].push（5）;console.log（obj1[2]）; //[3,4]console.log（obj2[2]）; //[3,4,5]