Please note, this is a STATIC archive of website www.w3resource.com from 19 Jul 2022, cach3.com does not collect or store any user information, there is no "phishing" involved.
w3resource

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

PHP Array: Exercise-49 with Solution

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
$first_array = array('c1' => 'Red', 'c2' => 'Green', 'c3' => 'White', 'c4' => 'Black'); 
$second_array = array('c2', 'c4'); 
print_r(array_intersect_key($first_array, array_flip($second_array)));
?>

Sample Output: 

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

Flowchart:

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

PHP Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a PHP function to set union of two arrays.
Next: Write a PHP script to get the last value of an array without affecting the pointer.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



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