Javascript Array

Question

I want to copy a two dimensional array by value, not by reference.

I tried "var arr2 = arr1.slice();"
but it didn't work.

When I do this for example, it changes arr1 and arr2.

var arr1 =[[1,2], [3,4]];
var arr2 = [arr1[0], arr1[1]];

arr2[0][1]=5;

So my question is:
How do I copy a two dimensional array by value in Javascript?

Answer 1

@tim Since, array is not a basic data type every element contains a reference In case of array of arrays.

So you need to do like this I guess:

https://code.sololearn.com/WMAbJHh5SAK9/?ref=app

Answer 2

arr1.slice() will work.
You have used I guess arr1.splice()

Answer 3

@Ashwani thank you very much!

@Mohammad, change "arr2[0]" to "arr2[0][0]" then you see what I mean :-|

Answer 4

Example code in playground please

Answer 5

@Tim, it seems slice() also use reference for inner array.

However you can use a little trick here.

first convert the arr1 to string then convert it back to a new array and assign it to arr2 variable.

Check out the updated code..

https://code.sololearn.com/Wm9VYi97J2VB/?ref=app

Answer 6

Use slice() method like this,

var arr2 = arr1.slice()

Answer 7

@tim

https://code.sololearn.com/Wm9VYi97J2VB/?ref=app