Question

I have an array of the following format:

array
  0 => 
    array
      1335541286 => 
        array
          'event' => string 'track' (length=5)
          'title' => string 'Plastic Humans' (length=14)
          'album' => string 'Cities of hunger' (length=16)
          'artist' => string 'The Maple Room' (length=14)
  1 => 
    array
      1335540999 => 
        array
          'event' => string 'track' (length=5)
          'title' => string 'Atlantis' (length=8)
          'album' => string 'Cities of hunger' (length=16)
          'artist' => string 'The Maple Room' (length=14)
  2 => 
    array
      1335540064 => 
        array
          'event' => string 'track' (length=5)
          'title' => string 'Doradus Stars' (length=13)
          'album' => string 'A Glimpse of the Inside' (length=23)
          'artist' => string 'The Maple Room' (length=14)
  3 => 
    array
      1335539855 => 
        array
          'event' => string 'track' (length=5)
          'title' => string 'In Twenty Five' (length=14)
          'album' => string 'A Glimpse of the Inside' (length=23)
          'artist' => string 'The Maple Room' (length=14)
  4 => 
    array
      1334016000 => 
        array
          'event' => string 'purchase' (length=8)
          'title' => string 'Donald Trump - Single' (length=21)
          'artist' => string 'Mac Miller' (length=10)
          'format' => string '10"' (length=3)

I would love to sort the array based on the key, which is the timestamp. I’ve read a lot about PHP sorting methods but i can’t figure out what the best solution would be.

Any help is appreciated,

Answer 1

using minified data:

$data = array(
  array('1335541286' => array('1')),
  array('1335540999' => array('1')),
  array('1335540064' => array('1')),
);

usort($data, function ($a, $b) {
  return key($a) - key($b);
});

print_r($data);

Also the structure of your input data seems a bit strange. The extra level is not really needed and complicates stuff unnecessarily.