PHP Array Exercises : Sort a multi-dimensional array set by a specific key

Last update on May 30 2022 11:45:10 (UTC/GMT +8 hours)

PHP Array: Exercise-23 with Solution

Write a PHP program to sort a multi-dimensional array set by a specific key.

Sample Solution:

PHP Code:

<?php
function column_Sort($unsorted, $column) { 
    $sorted = $unsorted; 
    for ($i=0; $i < sizeof($sorted)-1; $i++) { 
      for ($j=0; $j<sizeof($sorted)-1-$i; $j++) 
        if ($sorted[$j][$column] > $sorted[$j+1][$column]) { 
          $tmp = $sorted[$j]; 
          $sorted[$j] = $sorted[$j+1]; 
          $sorted[$j+1] = $tmp; 
      } 
    } 
    return $sorted; 
} 
$my_array = array(); 
$my_array[0]['name'] = 'Sana'; 
$my_array[0]['email'] = '[email protected]'; 
$my_array[0]['phone'] = '111-111-1234'; 
$my_array[0]['country'] = 'USA'; 

$my_array[1]['name'] = 'Robin'; 
$my_array[1]['email'] = '[email protected]'; 
$my_array[1]['phone'] = '222-222-1235'; 
$my_array[1]['country'] = 'UK'; 

$my_array[2]['name'] = 'Sofia'; 
$my_array[2]['email'] = '[email protected]'; 
$my_array[2]['phone'] = '333-333-1236'; 
$my_array[2]['country'] = 'India'; 
print_r(column_Sort($my_array, 'name')); 
?>

Sample Output:

Array                                                       
(                                                           
    [0] => Array                                            
        (                                                   
            [name] => Robin                                 
            [email] => [email protected]                    
            [phone] => 222-222-1235                         
            [country] => UK                                 
        )                                                   
                                                            
    [1] => Array                                            
        (                                                   
            [name] => Sana                                  
            [email] => [email protected]                     
            [phone] => 111-111-1234                         
            [country] => USA                                
        )                                                   
                                                            
    [2] => Array                                            
        (                                                   
            [name] => Sofia                                 
            [email] => [email protected]                    
            [phone] => 333-333-1236                         
            [country] => India                              
        )                                                   
                                                            
)

Flowchart:

PHP Code Editor:

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Previous: Write a PHP script to sort the following array by the day (page_id) and username.
Next: Write a PHP script to sort an array using case-insensitive natural ordering.

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC