PHP Array Exercises : Set union of two arrays

Last update on May 30 2025 13:14:40 (UTC/GMT +8 hours)

48. Set Union of Two Arrays

Write a PHP function to set union of two arrays.

Sample Solution:

PHP Code:

<?php
// Function to calculate the union of two arrays
function array_union($x, $y)
{ 
    // Use array_merge to combine three arrays:
    // 1. Intersection of $x and $y
    // 2. Elements in $x that are not in $y
    // 3. Elements in $y that are not in $x
    $aunion = array_merge(
        array_intersect($x, $y),   // Intersection of $x and $y
        array_diff($x, $y),        // Elements in $x but not in $y
        array_diff($y, $x)         // Elements in $y but not in $x
    );

    // Return the resulting array representing the union
    return $aunion;
}

// Example arrays
$a = array(1, 2, 3, 4);
$b = array(2, 3, 4, 5, 6);

// Call the function and display the result
print_r(array_union($a, $b));

?>

Output:

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

Flowchart:

For more Practice: Solve these Related Problems:

• Write a PHP function to compute the union of two arrays and return the resulting array containing all unique values.
• Write a PHP script to merge two arrays, remove duplicates, and display the final union array.
• Write a PHP program to calculate the union of arrays without using array_merge() and array_unique(), instead using loops.
• Write a PHP script to combine two arrays and then sort the union while preserving unique elements only.

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