sorting date associative array

Question

Possible Duplicate:
Sorting an associative array in PHP

I have this array

array
  0 => 
    array
      'start_date' => string '2012-11-14' (length=10)
      'end_date' => string '2012-11-19' (length=10)
  1 => 
    array
      'start_date' => string '1980-10-10' (length=10)
      'end_date' => string '1980-10-10' (length=10)
  2 => 
    array
      'start_date' => string '2012-11-20' (length=10)
      'end_date' => string '2099-10-10' (length=10)

I want to sort it on start_date. I dont think sort() method works on it. Any idea?

http://php.net/manual/en/function.usort.php – Blazemonger Oct 26 '12 at 18:47 — Blazemonger, Oct 26 '12 at 18:47

Yanick Rochon · Accepted Answer · 2012-10-26T18:52:25.863

2

You can use usort :

PHP 5.3+

usort($array, function($a, $b) {
   //return strtotime($a['start_date']) - strtotime($b['start_date']);
   return strcmp($a['start_date'], $b['start_date']);
});

Older versions of PHP

function startDateCmp($a, $b) {
   //return strtotime($a['start_date']) - strtotime($b['start_date']);
   return strcmp($a['start_date']), $b['start_date']);
}

usort($array, 'startDateCmp');

edited Oct 26 '12 at 18:52

answered Oct 26 '12 at 18:47

Yanick Rochon

45,203
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Actually, anonymous functions was introduced with php 5.3 – complex857 Oct 26 '12 at 18:48
in this particular case, strtotime is overkill. the dates are already in a string format that can be sorted directly. but otherwise yes, you'd have to convert to a timestamp before comparing. – Marc B Oct 26 '12 at 18:49
@MarcB, I like to play safe, but you're right :) – Yanick Rochon Oct 26 '12 at 18:50
@MarcB Assuming certain dates are formatted "2012-05-01" and not "2012-5-1", you're right. – Blazemonger Oct 26 '12 at 18:50

Chris Seymour · Answer 2 · 2012-10-26T19:05:10.680

1

Use usort and supply your own function to do the ordering.

function cmp($a, $b)
{
    return $b['start_date'], $a['start_date'];
}

usort($array, "cmp");

edited Oct 26 '12 at 19:05

answered Oct 26 '12 at 18:47

Chris Seymour

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sorting date associative array

2 Answers2

PHP 5.3+

Older versions of PHP