Why is this script not behaving like i would expect it to?

1 
function shuf(arr){
for(var i=arr.length-1;i>=1;i--){
  var temp=arr[i];
  var ran=Math.floor(Math.random()*i);
  arr[i]=arr[ran];
  arr[ran]=temp;
  return(arr);
}
}
function build() {

  var arr=[1,2,3,4];
  var arrB=[];
 for(var i=0;i<3;i++){
   arr=shuf(arr);
   arrB.push(arr);
 }
  return arrB;
}

this dosent do what I thought it would.
I thought it would give me an array of shuffled versions of arr.
like

[
[1,2,3,4,5],
[2,1,3,5,4],
[3,5,4,1,2]
]

but it gives me

[
[2,3,1,4,5],
[2,3,1,4,5],
[2,3,1,4,5]
]

it shuffles the first time, but not the rest…
I have no idea why that would be unless for some reason it will only run the shuf() function once inside a loop?

2

You return immediately in shuf, not after you’re done looping. There may be other problems on top of that.

1 Like
3

Wouldn’t I want that?
Arr=shuf(are)//arr becomes the value of shuf’s return.
Plus if it were returning after shuf, it wouldn’t push to ar three times

4

Let me put it differently. shuf() doesn’t do any looping. And the way you set it up, the first iteration doesn’t change anything.