Use a for loop to modify and store iterations of same array

Question

I'm trying to use a for loop to modify an array then store that modification in another array than do another modification and store that to the second array etc, but my second array is just d instances of the last iteration of my for loop. This seems like a closure problem but I can't figure out a workaround?

for (var d=1; d<arr1.length; d++) {
       remove = arr1.splice(d,1).toString(); 
        arr1.splice(d+1,0,remove);
     arr2.push(arr1);
   }
    return arr2;

I'm starting out with [1,2,3,4] as arr1 and I'm hoping to have arr2 end up as [[1,2,3,4],[1,3,2,4],[1,3,4,2]]. I think I need to change d — Keli, Feb 02 '17 at 22:06

score 0 · Answer 1 · answered Feb 02 '17 at 21:55

0

If you want to store all modified versions of your array, I suggest using an array of arrays, in this case let's call that top-level array master. Each time you modify your array, you would just push it to the master array.

This would give you what is called a "2d array". Then you would be able to access any version of your array that you wanted to. Your first array would be master[0], second would be master[1], etc. To access the first element of your second array, you can then just say master[1][0].

Hope this helps!

answered Feb 02 '17 at 21:55

minorcaseDev

181
5

I was trying to do that by pushing arr1 to arr2 each time? – Keli Feb 02 '17 at 22:15
I know your problem now. Arrays are reference objects. Read up on this http://stackoverflow.com/questions/1686990/javascript-variable-reference-alias – minorcaseDev Feb 02 '17 at 23:08
And this @keli http://docstore.mik.ua/orelly/webprog/jscript/ch04_04.htm – minorcaseDev Feb 02 '17 at 23:09

Use a for loop to modify and store iterations of same array

1 Answers1