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]
