PHP order array by date? [duplicate]

Question

I have some data from XML or JSON in a PHP array that looks like this:

[0]= array(2) {
    ["title"]= string(38) "Another title"
    ["date"]= string(31) "Fri, 17 Jun 2011 08:55:57 +0200"
}
[1]= array(2) {
    ["title"]= string(38) "My title"
    ["date"]= string(31) "Mon, 16 Jun 2010 06:55:57 +0200"
}

What I want to do is order the two items by date.

Is it possible to sort by date, when the sort value is inside every item?
Do I need to convert the date format to timestamp?

What I don't want to do

I could use date and set it as the ID but that don't feel right, because two items can have the same date and then it would not be unique.

Take a look at the first answer in this post: link

Sander
– Sander

2011-06-19 09:55:34 +00:00
Commented Jun 19, 2011 at 9:55 — Sander
– Sander, Commented Jun 19, 2011 at 9:55

KARASZI István · Accepted Answer · 2021-09-22 08:11:59Z

116

You don't need to convert your dates to timestamps before the sorting, but it's a good idea though because it will take more time to sort without this step.

$data = array(
    array(
        "title" => "Another title",
        "date"  => "Fri, 17 Jun 2011 08:55:57 +0200"
    ),
    array(
        "title" => "My title",
        "date"  => "Mon, 16 Jun 2010 06:55:57 +0200"
    )
);

function sortFunction( $a, $b ) {
    return strtotime($a["date"]) - strtotime($b["date"]);
}
usort($data, "sortFunction");
var_dump($data);

Update

In newer PHP versions you can use arrow functions too. Here you can find a more concise version of the above:

usort($data, fn ($a, $b) => strtotime($a["date"]) - strtotime($b["date"]));

edited Sep 22, 2021 at 8:11

answered Jun 19, 2011 at 9:58

KARASZI István

31.5k9 gold badges106 silver badges133 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Mojo Allmighty Over a year ago

Clean answer but this will lose values if two dates are equal

KARASZI István Over a year ago

That is not true, why would it? They would simply right after each other.

Will Over a year ago

how would I do desc order?

KARASZI István Over a year ago

Just flip the arguments in the substraction, from $b["date"] the $a["value"].

phihag · Accepted Answer · 2011-06-19 09:56:59Z

43

Use usort:

usort($array, function($a1, $a2) {
   $v1 = strtotime($a1['date']);
   $v2 = strtotime($a2['date']);
   return $v1 - $v2; // $v2 - $v1 to reverse direction
});

answered Jun 19, 2011 at 9:56

phihag

289k75 gold badges475 silver badges489 bronze badges

1 Comment

Guchelkaben Over a year ago

What about this version?

usort($sortArray, function ($a, $b) {             return strcmp($a['article_created_date'], $b['article_created_date']);   });

Ondřej Mirtes · Accepted Answer · 2011-06-19 09:58:26Z

29

I recommend using DateTime objects instead of strings, because you cannot easily compare strings, which is required for sorting. You also get additional advantages for working with dates.

Once you have the DateTime objects, sorting is quite easy:

usort($array, function($a, $b) {
  return ($a['date'] < $b['date']) ? -1 : 1;
});

answered Jun 19, 2011 at 9:58

Ondřej Mirtes

5,85128 silver badges39 bronze badges

Comments

Melsi · Accepted Answer · 2011-06-19 11:17:36Z

-2

He was considering having the date as a key, but worried that values will be written one above other, all I wanted to show (maybe not that obvious, that why I do edit) is that he can still have values intact, not written one above other, isn't this okay?!

<?php
 $data['may_1_2002']=
 Array(
 'title_id_32'=>'Good morning', 
 'title_id_21'=>'Blue sky',
 'title_id_3'=>'Summer',
 'date'=>'1 May 2002'
 );

 $data['may_2_2002']=
 Array(
 'title_id_34'=>'Leaves', 
 'title_id_20'=>'Old times',
  'date'=>'2 May   2002 '
 );


 echo '<pre>';
 print_r($data);
?>

edited Jun 19, 2011 at 11:17

answered Jun 19, 2011 at 10:00

Melsi

1,4371 gold badge15 silver badges22 bronze badges

Collectives™ on Stack Overflow

PHP order array by date? [duplicate]

4 Answers 4

Update

4 Comments

1 Comment

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Update

4 Comments

1 Comment

Comments

Comments

Linked

Related