PHP custom sorting

Question

I'm trying to sort an array of values.

The possible values in the array are 'neg_infinity',... {real numbers},.., 'infinity'

<?php
$a = array(
  array('column' => 3),
  array('column' => -1),
  array('column' => 1),
  array('column' => .1),
  array('column' => 2),
  array('column' => 'infinity'),
  array('column' => 'neg_infinity'),
  array('column' => 'infinity'),
);

I want:

    $a = array(
      array('column' => 'neg_infinity'),
      array('column' => -1),
      array('column' => .1),
      array('column' => 1),
      array('column' => 2),
      array('column' => 3),
      array('column' => 'infinity'),
      array('column' => 'infinity'),
    );

I've been playing around with uasort.

Anybody have a solution to his problem?

---

TEST DRIVER

<?php
function cmp($a, $b) {
    if ($a == $b) {
        return 0;
    }
    if ($a == 'neg_infinity') {
        return -1;
    }
    if ($a == 'infinity') {
        return 1;
    }
    return ($a < $b) ? -1 : 1;
}

$a = array('a' => 'infinity', 'b' => 8, 'c' => -1,'e' => 2, 'f' => 5, 'g' => 3, 'h' => -4, 'd' => 'neg_infinity');


uasort($a, 'cmp');


var_dump($a);

Answer 1

Use this for your sorting function:

function cmp($a, $b) {
    if ($a == 'neg_infinity') {
       return -1
    }
    if ($a == 'infinity') {
       return 1
    }
    return ($a < $b ? -1 : 1)
}

Answer 2

Something like this should work:

function cmp($a, $b) {
    if ($a == $b) {
        return 0;
    }
    if ($a == 'neg_infinity') {
        return -1;
    }
    if ($a == 'infinity') {
        return 1;
    }
    return ($a < $b) ? -1 : 1;
}