CODEWITHSUNDEEP
phparrayssortingmultidimensional-array
user348402
user348402

Reputation: 228

Sort an associative array by Y-m-d formatted keys

Does anybody have an idea how can I sort this array by key (date) in PHP?

Array
(   
    [2011-02-16] => Array
        (
            [date] => 2011-02-16
            [num] => 2
        )

    [2011-02-11] => Array
        (
            [date] => 2011-02-11
            [num] => 0
        )

    [2011-02-17] => Array
        (
            [date] => 2011-02-17
            [num] => 0
        )

    [2011-02-18] => Array
        (
            [date] => 2011-02-18
            [num] => 0
        )

)

Upvotes: 2

Views: 481

Answers (9)

John Smith
John Smith

Reputation: 1780

A better answer would be to use uksort which is used to sort keys with a user-defined function (considering that these dates cannot always be compared and cannot be sorted with ksort without first applying strtotime to the keys):

function sort_by_date_keys($date_key1, $date_key2) {
    // reverse the order of the $date_keys for "oldest to newest"
    return strtotime($date_key2) - strtotime($date_key1);
);

uksort($array, 'sort_by_date_keys');

This method is more defined than uasort as it was tailored for keys.

Example:

$array = array(
    '1/1/12' => 'foo1',
    '1/1/13' => 'foo2'
);
uksort($array, 'sort_by_date_keys');

// output
$array = array(
    '1/1/13' => 'foo2',
    '1/1/12' => 'foo1'
);

Upvotes: 0

Alexandru Petrescu
Alexandru Petrescu

Reputation: 3479

What you want is UASORT.

https://www.php.net/manual/en/function.uasort.php

function would be like:

function cmp($a, $b) {
    $d1 = strtotime($a['date']);
    $d2 = strtotime($b['date']);
    if ($d1 == $d2) {
       return 0;
    }
    return ($d1 < $d2) ? -1 : 1;
}

Upvotes: 0

Colin O&#39;Dell
Colin O&#39;Dell

Reputation: 8647

http://www.php.net/manual/en/function.array-multisort.php

Would example #3 suit your needs?

Upvotes: 0

Tesserex
Tesserex

Reputation: 17314

Since your array already has the date in the keys, why not just use ksort? The string comparison should work fine since you're using YYYY-MM-dd format.

Upvotes: 0

madmik3
madmik3

Reputation: 6973

have you tried ksort? http://www.php.net/manual/en/function.ksort.php

Upvotes: 2

Paul Dixon
Paul Dixon

Reputation: 300845

Well, as sorting on the key would do it, ksort() would work for you!

But if you really want to sort on the date element, you would use uasort() with a sort function like this

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

  uasort($myarray, 'compare');

Upvotes: 0

diagonalbatman
diagonalbatman

Reputation: 18002

This should help you brush up on the basics of array sorting in PHP

http://www.the-art-of-web.com/php/sortarray/

Something like this would sort your problem however:

usort($array, "cmp");

function cmp($a, $b){ 
    return strcmp($b['date'], $a['date']);

Upvotes: 0

Dutchie432
Dutchie432

Reputation: 29160

Sure thing. I answered this exact post yesterday, too.

Sorting 2 arrays to get the highest in one and lowest in another

In your case, it will be something like...

$myArray= subval_sort($myArray,'date'); 

function subval_sort($a,$subkey) {
    foreach($a as $k=>$v) {
        $b[$k] = strtolower($v[$subkey]);
    }
    asort($b);
    foreach($b as $key=>$val){
        $c[] = $a[$key];
    }
    return $c;
}

EDIT

The answer by shamittomar is better though :)

Upvotes: 0

shamittomar
shamittomar

Reputation: 46692

Use the uasort function, which is user customizable sorting. Like this:

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

uasort($your_array, "cmp");

Upvotes: 7

Related Questions