I want to make a clone of multidimensional Array so that i can play arround with the clone array without affecting main Array.
Array.prototype.clone = function () {
var newArray = new Array(this.length);
for(var i=0; i < this.length; i++ ){
newArray[i] = this[i];
}
return newArray;
};
But problem which is since it is using array prototype so it will clone my all array.so can any body tell me what is the best way of doing this.
vsync is correct, my first answer doesn't handle var a = [[1,2],[3,4]];
So here's an improved version
var a = [[1,2],[3,4]];
Array.prototype.clone = function() {
var arr = this.slice(0);
for( var i = 0; i < this.length; i++ ) {
if( this[i].clone ) {
//recursion
arr[i] = this[i].clone();
}
}
return arr;
}
var b = a.clone()
console.log(a);
console.log(b);
b[1][0] = 'a';
console.log(a);
console.log(b);
//[[1, 2], [3, 4]]
//[[1, 2], [3, 4]]
//[[1, 2], [3, 4]]
//[[1, 2], ["a", 4]]
if( this[i] && this[i].clone ) { to support sparse arrays (or whatever you call it when some values are null)You need to use recursion
var a = [1,2,[3,4,[5,6]]];
Array.prototype.clone = function() {
var arr = [];
for( var i = 0; i < this.length; i++ ) {
// if( this[i].constructor == this.constructor ) {
if( this[i].clone ) {
//recursion
arr[i] = this[i].clone();
break;
}
arr[i] = this[i];
}
return arr;
}
var b = a.clone()
console.log(a);
console.log(b);
b[2][0] = 'a';
console.log(a);
console.log(b);
/*
[1, 2, [3, 4, [5, 6]]]
[1, 2, [3, 4, [5, 6]]]
[1, 2, [3, 4, [5, 6]]]
[1, 2, ["a", 4, [5, 6]]]
*/
Any other objects in the original array will be copied by reference though
clone method on each object in the array, and call it to clone the object if present. This will handle the recursion of arrays and also allow any other objects with clone methods to be deep-copied as well.
var a = [[1,2],[3,4]];I found that this approach is better than meouw's :
var source = [
[1, 2, {c:1}],
[3, 4, [5, 'a']]
];
// Create a new method ontop of the "Array" primitive prototype:
Array.prototype.clone = function() {
function isArr(elm) {
return String(elm.constructor).match(/array/i) ? true : false;
}
function cloner(arr) {
var arr2 = arr.slice(0),
len = arr2.length;
for (var i = 0; i < len; i++)
if (isArr(arr2[i]))
arr2[i] = cloner(arr2[i]);
return arr2;
}
return cloner(this);
}
// Clone
var copy = source.clone();
// modify copy
copy[0][0] = 999;
console.dir(source);
console.dir('**************');
console.dir(copy);String, Numbers, Objects) :var source = [
[1,2, {a:1}],
["a", "b", ["c", 1]]
];
// clone "srouce" Array
var copy = JSON.parse(JSON.stringify(source));
// modyfy clone
copy[0][0] = 999;
// print both arrays
console.dir(copy)
console.log('***********')
console.dir(source)
