PHP Array Exercises : Filter a multi-dimensional array and get those items that will match with the specified value

Last update on May 30 2022 11:43:03 (UTC/GMT +8 hours)

PHP Array: Exercise-52 with Solution

Write a PHP function to filter a multi-dimensional array. The function will return those items that will match with the specified value.

Sample Solution:

PHP Code:

<?php
    function array_filter_by_value($my_array, $index, $value)
    { 
        if(is_array($my_array) && count($my_array)>0)  
        { 
            foreach(array_keys($my_array) as $key){ 
                $temp[$key] = $my_array[$key][$index]; 
                 
                if ($temp[$key] == $value){ 
                    $new_array[$key] = $my_array[$key]; 
                } 
            } 
          } 
      return $new_array; 
    } 
$colors = array( 
   0 => array('key1' => 'Red', 'key2' => 'Green', 'key3' => 'Black'), 
   1 => array('key1' => 'Yellow', 'key2' => 'White', 'key3' => 'Pink') 
); 
$results = array_filter_by_value($colors, 'key2', 'White');     
print_r($results);      
?>

Sample Output:

Array                                                       
(                                                           
    [1] => Array                                            
        (                                                   
            [key1] => Yellow                                
            [key2] => White                                 
            [key3] => Pink                                  
        )                                                   
                                                            
)

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to filter out some array elements with certain key-names.
Next: Write a PHP script to delete a specific value from an array using array_filter() function.

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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