PHP Array Exercises : Get an array of all elements which have the keys that are present in another array

Last update on May 30 2025 13:13:53 (UTC/GMT +8 hours)

49. Get Array Entries with Specific Keys

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.

Sample Solution:

PHP Code:

<?php
// Original associative array
$first_array = array('c1' => 'Red', 'c2' => 'Green', 'c3' => 'White', 'c4' => 'Black'); 

// Array containing keys to check for intersection
$second_array = array('c2', 'c4'); 

// Use array_flip to swap keys and values, then apply array_intersect_key to find common keys
$result = array_intersect_key($first_array, array_flip($second_array));

// Display the result
print_r($result);

?>

Output:

Array                                                       
(                                                           
    [c2] => Green                                           
    [c4] => Black                                           
)

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to filter an associative array and return a new array containing only the entries whose keys are present in a second array.
Write a PHP function to compare the keys of an array against a given list and output the matched key-value pairs.
Write a PHP program to use array_intersect_key() to extract a subset of an array based on a provided keys array.
Write a PHP script to manually loop through an associative array and build a new array from entries matching specified keys.

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