How to replace array elements with another given array elements?

Question

I want to make a function that completely override the original array.

function putDatainthis(arr) {
 //....some ways to get data
 arr = [data,data,data...]; //this just reassigns arr = to new array original that was passed as reference hasn't been modified.
}

//so right now only way i can think of is this:

function putDatainthis(arr) {
 var data = [3,4,6,2,6,1];
 arr.length=0;
 data.forEach(function(e){
 arr.push(e);
 });
}

but i want to know can it be improved or is there more native way.

• Muhammad Umer: basically i want replace function

Answer 1

The Array.prototype.splice() function is what you are looking for, this is your way to go:

function putDataInThis(arr) {
 var data = [3, 4, 6, 2, 6, 1];
 arr.length = 0;
 arr.splice(0, arr.length, data);
 return arr;
}
alert(putDataInThis(["h", "g"]).join(","));

Explantation:

In the following arr.splice(0, arr.length, data) statement, we used splice() function with the following parameters:

• 0 the beginning index for the replacement.
• arr.length as the number of elements to replace.
• And data is the list of new values to put in our array.

Read Array.splice( ): insert, remove, or replace array elements for further information.

Answer 2

I think you could use jquery merge.

function putDatainthis(arr) {
 var data = [3,4,6,2,6,1];
 $.merge(arr, data);
}

• Muhammad Umer: i will be using it in nodejs

Answer 3

Try this way.

function putDatainthis(arr) {
 var data = [3,4,6,2,6,1]; 
 var concat_array = data.concat(arr);
}

• Muhammad Umer: arr has not changed in this example