{"id":1090,"date":"2021-04-13T09:04:53","date_gmt":"2021-04-13T09:04:53","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=1090"},"modified":"2025-04-06T07:22:09","modified_gmt":"2025-04-06T07:22:09","slug":"php-array_map","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-array_map\/","title":{"rendered":"PHP array_map"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you will learn how to use the PHP array_map()<\/code> function that creates a new array whose elements result from applying a callback to each element.<\/p>\n\n\n\n

Introduction to the PHP array_map() function #<\/a><\/h2>\n\n\n\n

Suppose that you have an array<\/a> that holds the lengths of squares:<\/p>\n\n\n

<?php<\/span>\n\n$lengths = [10<\/span>, 20<\/span>, 30<\/span>];<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
<?php<\/span>\n\n$lengths = [10<\/span>, 20<\/span>, 30<\/span>];\n\n\/\/ calculate areas<\/span>\n$areas = [];\n\nforeach<\/span> ($lengths as<\/span> $length) {\n\t$areas[] = $length * $length;\n}\n\nprint_r($areas);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
Array<\/span>\n(\n    [0<\/span>] => 100<\/span>\n    [1<\/span>] => 400<\/span>\n    [2<\/span>] => 900<\/span>\n)<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The foreach<\/code> iterates over the elements of the $lengths<\/code> array, calculates the area of each square, and adds the result to the $areas<\/code> array.<\/p>\n\n\n\n
Alternatively, you can use the array_map()<\/code> function that achieves the same result:<\/p>\n\n\n
<?php<\/span>\n\n$lengths = [10<\/span>, 20<\/span>, 30<\/span>];\n\n\/\/ calculate areas<\/span>\n$areas = array_map(function<\/span> ($length)<\/span> <\/span>{\n\treturn<\/span> $length * $length;\n}, $lengths);\n\n\nprint_r($areas);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the array_map()<\/code> applies an anonymous function<\/a> to each element of the $lengths<\/code> array. It returns a new array whose elements are the results of the anonymous function.<\/p>\n\n\n\n
From PHP 7.4, you can use an arrow function<\/a> instead of an anonymous function like this:<\/p>\n\n\n
<?php<\/span>\n\n$lengths = [10<\/span>, 20<\/span>, 30<\/span>];\n\n\/\/ calculate areas<\/span>\n$areas = array_map(\n\tfn ($length) => $length * $length,\n\t$lengths\n);\n\nprint_r($areas);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
PHP array_map() function syntax #<\/a><\/h2>\n\n\n\n
The following shows the array_map()<\/code> function syntax:<\/p>\n\n\n
array_map ( callable|null<\/span> $callback , array<\/span> $array , array<\/span> ...$arrays ) : array<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The array_map()<\/code> has the following parameters:<\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
To calculate the areas of the squares, you may come up with the foreach<\/a><\/code> loop like this:<\/p>\n\n\n