Sorting grouped multi-dimensional array by value

Question

$data = array(
    'apple' => array(
        0 => array('sort'=>4, 'name'=>'apple_4'),
        1 => array('sort'=>10, 'name'=>'apple_10'),
        2 => array('sort'=>5, 'name'=>'apple_5'),
        3 => array('sort'=>1, 'name'=>'apple_1')
        ),

    'orange' => array(
        0 => array('sort'=>4, 'name'=>'orange_4'),
        1 => array('sort'=>10, 'name'=>'orange_10')
        )
    );

Need assistance sorting multi-dimensional array. For the array above, I would like to sort the contents of each group in descending order by the 'sort' value. The group's keys should remain in tact (apple, orange) but content's keys are not important.

Data should be ordered:

apple
- apple_10
- apple_5
- apple_4
- apple_1
orange
- orange_10
- orange_4

possible duplicate of [Reference: all basic ways to sort arrays and data in PHP](http://stackoverflow.com/questions/17364127/reference-all-basic-ways-to-sort-arrays-and-data-in-php) — baao, Aug 01 '15 at 00:57

score 1 · Accepted Answer · edited Aug 01 '15 at 01:04

1

Use usort() to sort the array:

foreach($data as &$value) {
    usort($value,function($a,$b) {
        return $b['sort'] - $a['sort'];
    });
}

edited Aug 01 '15 at 01:04

Rizier123

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answered Aug 01 '15 at 00:48

FuzzyTree

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@LouisW if the field you're sorting by isn't a string, you should use the updated code – FuzzyTree Aug 01 '15 at 00:54
1

^^ Will remove the other comments, since everything is cleared. (An alternative to the foreach loop to add this here would be to use `array_walk()`, e.g. `array_walk($data, function(&$value){/* usort() here */}`) – Rizier123 Aug 01 '15 at 01:03

score 0 · Answer 2 · answered Aug 01 '15 at 00:57

$data = array(                                                                  
    'apple' => array(                                                           
        0 => array('sort'=>4, 'name'=>'apple_4'),                               
        1 => array('sort'=>10, 'name'=>'apple_10'),                             
        2 => array('sort'=>5, 'name'=>'apple_5'),                               
        3 => array('sort'=>1, 'name'=>'apple_1')                                
    ),                                                                          

    'orange' => array(                                                          
        0 => array('sort'=>4, 'name'=>'orange_4'),                              
        1 => array('sort'=>10, 'name'=>'orange_10')                             
    )                                                                           
);                                                                              

foreach($data as &$value) {                                                        
    usort($value, function($a, $b) {                                            
        return $a['sort'] < $b['sort'];                                         
    });                                                                                                                                       
}

Sorting grouped multi-dimensional array by value

2 Answers2