前面的話
前面的博文中介紹了對象拷貝，本文將詳細介紹數組復制
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
使用該方法的缺點是數組中的項全部變成了字符串形式
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] 深拷貝
以上方法實現的僅是數組的淺拷貝，如果要實現數組的深拷貝，需要使用遞歸方法
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]新聞熱點
疑難解答
