PHP Exercises: Retrieve all of the values for a given key

Last update on May 30 2022 11:50:08 (UTC/GMT +8 hours)

PHP: Exercise-87 with Solution

Write a PHP program to retrieve all of the values for a given key.

Sample Solution: -

PHP Code:

<?php
function pluck($items, $key)
{
    return array_map( function($item) use ($key) {
        return is_object($item) ? $item->$key : $item[$key];
    }, $items);
}
print_r(pluck([
    ['product_id' => 'p100', 'name' => 'Computer'],
    ['product_id' => 'p200', 'name' => 'Laptop'],
], 'name'));

?>

Sample Output:

Array
(
    [0] => Computer
    [1] => Laptop
)

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to get the last element of a given list.
Next: Write a PHP program to mutate the original array to filter out the values specified.

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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