Confused about syntax when using for loop to add to array

Question

I recently came across the following piece of sample code:

function range(upto) {
  var result = [];
  for (var i = 0; i <= upto; i++) {
    result[i] = i;
  }
  return result;
}

and I'm confused as to why:

result[i] = i;

as opposed to:

i = result[i];

Isn't 'i' the variable and 'result[i]' the value?

No, result[i] is the variable and i is the value it is being set to. The purpose of that line of code is to set the variable result[i] to the value i. — David Schwartz
– David Schwartz, Commented Sep 7, 2013 at 20:11

Denys Séguret · Accepted Answer · 2013-09-07 20:10:38Z

2

This fills the array :

result[0] = 0 // sets the first cell of the array to the value 0
result[1] = 1
etc.

This function returns

[0, 1, 2, ... upto]

answered Sep 7, 2013 at 20:10

Denys Séguret

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Comments

NPE · Accepted Answer · 2013-09-07 20:11:08Z

1

The

result[i] = i;

assigns the value of i to the i-th element of result.

Thus, result[0] becomes 0, result[1] becomes 1 and so on.

answered Sep 7, 2013 at 20:11

NPE

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Arup Rakshit · Accepted Answer · 2013-09-07 20:13:13Z

0

result[i] = i; means you are assigning the value of i to the index i of the array result.
i = result[i]; means you are assigning the value of the i-th index of the array result,to the variable i.

That's it.

answered Sep 7, 2013 at 20:13

Arup Rakshit

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