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

Last update on May 27 2025 13:08:27 (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.

Go to:

• PHP Basic Exercises Home ↩
• PHP Exercises Home ↩

PREV : Retrieve the Last Element of a List.
NEXT : Mutate Array to Filter Out Specified Values.

PHP Code Editor:

Click to Open Editor

Have another way to solve this solution? Contribute your code (and comments) through Disqus.