PHP Sort multidimensional array by field name

Question

I tried to adapt this code to sort a multidimensional array by the named key / field. The field is an integer needed to sort the smallest in size.

function myCmp($a, $b)
{
    return strcmp($a["days"], $b["days"]);
}

uasort($myArray, "myCmp");

This sorts the arrays as needed, but in the wrong order. At the moment, it sorts from the largest to the smallest, without using the natural order. I need to sort the smallest in size in natural order (e.g. 2 to 5, 12 and 24).

Answer 1

strnatcmp () is your friend

. ( php 5.3/ ):

<?php
$myArray = array( 'foo'=>array('days'=>2), 'bar'=>array('days'=>22), 'ham'=>array('days'=>5), 'egg'=>array('days'=>12) );
uasort($myArray, function($a, $b) { return strnatcmp($a["days"], $b["days"]); });

foreach($myArray as $k=>$v) {
  echo $k, '=>', $v['days'], "\n";
}

foo=>2
ham=>5
egg=>12
bar=>22

Answer 2

strcmp:

function myCmp($a, $b)
{
  return strcmp($b["days"], $a["days"]);
}

uasort($myArray, "myCmp");

Answer 3

Since you want to sort in a natural order, you should not use strcmp, you can do:

function myCmp($a, $b)
{
  if ($a['days'] == $b['days']) return 0;
  return ($b['days'] > $a['days']) ? -1 : 1;
}

Here is a working example .