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-   -   Adding Array To Another Array (http://www.daniweb.com/forums/thread158893.html)

jobojo Nov 22nd, 2008 1:26 am
Adding Array To Another Array
 
I need to add an array to the end of another array. I understand how to do this using the concat, join, and push methods. However, I need to do this using a loop (I am pretty sure a 'for' loop is the right choice), however, I can not figure out how to do this with a for loop.

arr1 = [1,2,3,4]
arr2 = [5,6,7,8]

All I need to do is add arr2 on to the end of arr1 using a loop to do this, but I have not been able to figure out how to do this. Does anyone have any suggestions or can someone please lead me in the right direction. Thanks in advance for any suggestions and/or assistance.

DangerDev Nov 22nd, 2008 1:46 am
Re: Adding Array To Another Array
 
Hi,
define a new array with function: arr3=new Array(no_of_element);
then use for loop to populate member of both array in to it as u want.

use arr_var[index] to access individual member of array.

sasankasekhar Nov 22nd, 2008 2:16 am
Re: Adding Array To Another Array
 
Quote:

Originally Posted by DangerDev (Post 741915)
Hi,
define a new array with function: arr3=new Array(no_of_element);
then use for loop to populate member of both array in to it as u want.

use arr_var[index] to access individual member of array.

This would help:
function addArr(){
var arr1 =  [1,2,3,4];
var arr2 =  [5,6,7,8];
arr3=arr1;//or u can use  arr1 itself;
for(i=arr1.length,j=0;j<arr2.length;i++){ 
        arr3[i]=arr2[j];
        j++;
}
for(i=0;i<arr3.length;i++)
        document.writeln(arr3[i]);
}

Regards ...

essential Nov 22nd, 2008 4:19 am
Re: Adding Array To Another Array
 
Just a quick brief regarding arrays. Since an Array can store other Arrays you can get the benefit of multi-dimension arrays.

var x=[0,1,2,3,4,5]; var y=[x];

In the above example i've created an array named "x" and assigned it as the first element in the array "y". If we ask for the value of y[0] it will return the contents of "x" as a string because we didn't specify an index.

var x=[0,1,2,3,4,5]; var y=[x]; document.writeln(y[0]); // Will output: 0,1,2,3,4,5

If we wanted the third index we'd access it this way...

var x=[0,1,2,3,4,5]; var y=[x]; document.writeln(y[0][3]); // Will output: 2

There's no defined limit to how many Arrays you can nest in this manner. For instance...

document.writeln(bigArray[5][8][12][1])

...would indicate bigArray's 5th index held an array, who's 8th index held an array, who's 12th index held an array, who's first index contains the data we want.

essential Nov 22nd, 2008 4:49 am
Re: Adding Array To Another Array
 
Or you can simply do it with the push() method. Code is as follow:
<script type="text/javascript">
var arr1 = [1,2,3,4];
var arr2 = [5,6,7,8];
for (var x = 0; x <= arr2.length; x++) {
    arr1.push(arr2[x]) }
document.write(arr1 + '<br />')
</script>
hope it clears you up, and good day to you...

jobojo Nov 22nd, 2008 5:35 pm
Re: Adding Array To Another Array
 
Thank you for all of the responses. I have tried all of the advice and gotten all of it to work for me and I have a better understanding now.

Essential, thanks for the additional tips and information regarding arrays and their usage, it was greatly appreciated. Your final code with the push method was exactly how I was originally trying to figure the problem out and I was very close except I was off by a couple of minor details. Apparently, I was writing the push method portion incorrectly. Thanks again for all of your help and have a wonderful holiday season everyone:)


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