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]

tag：数组复制详解电脑软件Javascript