What does array_map() do in PHP?

array_map() applies a callback function to each element of an array and returns a new array with the transformed values. Example: array_map(fn($n) => $n * 2, [1,2,3]) returns [2,4,6].

What is the difference between array_map() and array_filter()?

array_map() transforms elements (returns same count), while array_filter() removes elements based on a condition (may return fewer elements).

Can array_map() work with multiple arrays?

Yes, pass multiple arrays and a callback that accepts multiple parameters: array_map(fn($a, $b) => $a + $b, $arr1, $arr2).

PHP array_map() Function

Array Function PHP 4.0.6+

The array_map() function applies a callback function to each element of an array and returns a new array with the results.

Syntax

array_map(?callable $callback, array $array, array ...$arrays): array

Parameters

Parameter	Type	Description
`$callback`	callable\|null	A callback function to apply to each element
`$array`	array	The array to process
`$arrays`	array	Additional arrays (optional)

Return Value

Returns a new array containing the results of applying the callback function to each element.

Try It Online

<?php
// array_map() - Apply callback to array elements
// Returns a new array with transformed elements

// Example 1: Square numbers
$numbers = [1, 2, 3, 4, 5];
echo "Original: [" . implode(", ", $numbers) . "]\n";

$squared = array_map(fn($n) => $n * $n, $numbers);
echo "Squared:  [" . implode(", ", $squared) . "]\n\n";

// Example 2: Transform strings
$names = ["john", "jane", "bob"];
echo "Names (lowercase): [" . implode(", ", $names) . "]\n";

$capitalized = array_map('ucfirst', $names);
echo "Names (capitalized): [" . implode(", ", $capitalized) . "]\n\n";

// Example 3: Extract from array of arrays
$users = [
    ["name" => "Alice", "age" => 25],
    ["name" => "Bob", "age" => 30],
    ["name" => "Charlie", "age" => 35]
];

$names = array_map(fn($user) => $user['name'], $users);
echo "Extracted names: [" . implode(", ", $names) . "]\n\n";

// Example 4: Multiple arrays
$prices = [10, 20, 30];
$quantities = [2, 3, 1];

$totals = array_map(
    fn($price, $qty) => $price * $qty,
    $prices,
    $quantities
);
echo "Prices:     [" . implode(", ", $prices) . "]\n";
echo "Quantities: [" . implode(", ", $quantities) . "]\n";
echo "Totals:     [" . implode(", ", $totals) . "]\n";

Output

Click Run to execute your code

More Examples

Using Built-in Functions

<?php
$names = ["john", "jane", "bob"];

// Capitalize all names
$capitalized = array_map('ucfirst', $names);
print_r($capitalized);
// ["John", "Jane", "Bob"]
?>

Using Arrow Functions (PHP 7.4+)

<?php
$numbers = [1, 2, 3, 4, 5];

// Square each number
$squares = array_map(fn($n) => $n * $n, $numbers);
print_r($squares);
// [1, 4, 9, 16, 25]
?>

Multiple Arrays

<?php
$first = ["John", "Jane"];
$last = ["Doe", "Smith"];

// Combine first and last names
$full = array_map(fn($f, $l) => "$f $l", $first, $last);
print_r($full);
// ["John Doe", "Jane Smith"]
?>

With null Callback (Zip Arrays)

<?php
$a = [1, 2, 3];
$b = ['a', 'b', 'c'];

$zipped = array_map(null, $a, $b);
print_r($zipped);
// [[1, 'a'], [2, 'b'], [3, 'c']]
?>

Tip: Unlike array_filter(), array_map() always returns an array with the same number of elements as the input.

Common Use Cases

Transforming data (e.g., formatting prices, dates)
Extracting values from objects/arrays
Applying calculations to all elements
Converting data types

Related Functions

array_filter() - Filter array elements
array_keys() - Get array keys
array_values() - Get array values

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