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PHP Array Exercises : Set union of two arrays

PHP Array: Exercise-48 with Solution

Write a PHP function to set union of two arrays.

Sample Solution:

PHP Code:

<?php
function array_union($x, $y)
   { 
      $aunion=  array_merge(
            array_intersect($x, $y),
            array_diff($x, $y),     
            array_diff($y, $x)      
        );
        return $aunion;
   }
$a = array(1, 2, 3, 4);
$b = array(2, 3, 4, 5, 6);
print_r(array_union($a, $b));
?>

Sample Output: 

Array                                                       
(                                                           
    [0] => 2                                                
    [1] => 3                                                
    [2] => 4                                                
    [3] => 1                                                
    [4] => 5                                                
    [5] => 6                                                
)

Flowchart:

Flowchart: PHP - Set union of two arrays

PHP Code Editor:

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Previous: Write a PHP function to get an array with the first key and value.
Next: Write a PHP script to get an array containing all the entries of an array which have the keys that are present in another array.

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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