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

Last update on May 27 2025 13:09:13 (UTC/GMT +8 hours)

87. Retrieve All Values for a Given Key

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

Sample Solution:

PHP Code:

<?php
// Function definition for 'pluck' that takes an array of items and a key as parameters
function pluck($items, $key)
{
    // Use 'array_map' to apply a callback function to each element of the array
    return array_map( function($item) use ($key) {
        // Check if the item is an object, and if so, access the property specified by the key
        // If the item is an array, access the array element specified by the key
        return is_object($item) ? $item->$key : $item[$key];
    }, $items);
}

// Call 'pluck' with an array of associative arrays and a key, then display the result using 'print_r'
print_r(pluck([
    ['product_id' => 'p100', 'name' => 'Computer'],
    ['product_id' => 'p200', 'name' => 'Laptop'],
], 'name'));

?>

Explanation:

Function Definition:

The function pluck is defined to take two parameters:

$items: an array of items (either associative arrays or objects).
$key: a string representing the key or property to extract from each item.

Using array_map:

Inside the function, array_map is utilized to iterate over each element in the $items array.
A callback function is defined within array_map.

Extracting Values:

The callback function checks if the current item is an object:

If it is an object, it accesses the property specified by $key (e.g., $item->$key).
If it is an array, it accesses the array element specified by $key (e.g., $item[$key]).

Return Statement:

The modified array containing only the values associated with the specified key is returned.

Example Usage:

The pluck function is called with an array of associative arrays and the key 'name':

It extracts the names of the products from the input array.

The result is displayed using print_r.

Purpose:

The pluck function is useful for extracting a specific property or value from an array of objects or associative arrays, effectively creating a new array containing only those values.

Output:

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

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to traverse an array of associative arrays and return all values for a specified key.
Write a PHP function to extract column values from an array of records based on a given key.
Write a PHP script to compile and output a list of all entries that share a common key from a multidimensional array.
Write a PHP script to filter an array and retrieve all values associated with a target key using array_column.

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PHP Code Editor:

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