PHP: Filling in the 'gaps' in an array

Question

Hey gurus,

I've got a php array (obtained through checkbox values in a form - as you know checkboxes only show up in the _POST variable when they are not set).

Array
(
    [2] => 0,2
    [3] => 0,3
)

I need a way to 'fill in' the gaps between the range 0-5. So above would look like (filling the empty spaces with '-1'. I tried array_merge() with an array filled with '-1' but that didn't work.

Array
(
    [0] => -1
    [1] => -1
    [2] => 0,2
    [3] => 0,3
    [4] => -1
    [5] => -1
)

I think I may have gone down the wrong road with the problem I am trying to solve, but I have put too much time into this solution to back out - a feeling I am sure most of you are familiar with(!)

Cheers!

Answer 1

Why not just do it in a loop?

for ($i = 0; $i <= 5; $i++)
{
    if (!isset($array[$i]))
    {
        $array[$i] = -1;
    }
}

Answer 2

If you array is variable length you would want to use:

  for ($i = 0; $i <= sizeof($array); $i++)
    {
        if (!isset($array[$i]))
        {
            $array[$i] = -1;
        }
    }

Answer 3

array_merge doesn't work, but '+' does!

$a = array(2 => 22, 3 => 33);
$b = $a + array_fill(0, 6, -1);

the key order is wrong though, so you might want to ksort it.

Answer 4

You don't need to fill any gaps