Move all odd-keyed elements to the back of the array

Question

I have an array with numeric keys and I need to move all elements with odd keys to the end of the array.

[
    0 => 'apples',
    1 => 'oranges',
    2 => 'peaches',
    3 => 'pears',
    4 => 'watermelon'
]

What I am looking to do is something like this

[
    0 => 'apples',
    2 => 'peaches',
    4 => 'watermelon',
    1 => 'oranges',
    3 => 'pears'
]

It does not matter if the array keys change or not, I just need the location of the values to change.

Answer 1

<?php
$fruit = array('apples', 'oranges', 'peaches', 'pears', 'watermelon');

function fruitCmp($a, $b) {
    if ($a == $b) {
        return 0;
    }

    $aIsOdd = $a % 2;
    $bIsOdd = $b % 2;

    if (($aIsOdd && $bIsOdd) || (!$aIsOdd && !$bIsOdd)) {
        return $a < $b ? -1 : 1;
    }

    if ($aIsOdd && !$bIsOdd) {
        return 1;
    }

    if (!$aIsOdd && $bIsOdd) {
        return -1;
    }
}

uksort($fruit, 'fruitCmp');

var_dump($fruit);

Output:

array(5) {
  [0]=>
  string(6) "apples"
  [2]=>
  string(7) "peaches"
  [4]=>
  string(10) "watermelon"
  [1]=>
  string(7) "oranges"
  [3]=>
  string(5) "pears"
}