{"id":776,"date":"2021-03-27T10:20:13","date_gmt":"2021-03-27T10:20:13","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=776"},"modified":"2025-04-07T13:45:57","modified_gmt":"2025-04-07T13:45:57","slug":"php-anonymous-functions","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-anonymous-functions\/","title":{"rendered":"PHP Anonymous Functions"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you will learn about PHP anonymous functions and how to use them effectively.<\/p>\n\n\n\n

Introduction to anonymous functions #<\/a><\/h2>\n\n\n\n

When you define a function<\/a>, you specify a name for it. Later, you can call the function by its name.<\/p>\n\n\n\n

For example, to define a function that multiplies two numbers, you can do it as follows:<\/p>\n\n\n

<?php<\/span>\n\nfunction<\/span> multiply<\/span>($x, $y)<\/span>\n<\/span>{\n\treturn<\/span> $x * $y;\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The multiply()<\/code> function accepts two arguments and returns the result. To call the multiply()<\/code> function, you pass the arguments to it like this:<\/p>\n\n\n
<?php<\/span>\n\nmultiply(10<\/span>, 20<\/span>);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the multiply()<\/code> is a named function. And you can reuse it as many times as you want.<\/p>\n\n\n\n
Besides named functions, PHP allows you to define anonymous functions.<\/p>\n\n\n\n
An anonymous function is a function that doesn’t have a name.<\/p>\n\n\n\n
The following example defines an anonymous function that multiplies two numbers:<\/p>\n\n\n
<?php<\/span>\n\nfunction<\/span> ($x, $y)<\/span> <\/span>{\n\treturn<\/span> $x * $y;\n};<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Since the function doesn’t have a name, you need to end it with a semicolon (;<\/code>) because PHP treats it as an expression.<\/p>\n\n\n\n
This anonymous function is useless because you cannot use it like a named function.<\/p>\n\n\n\n
The following example assigns the anonymous function to the $multiply<\/code> variable:<\/p>\n\n\n
<?php<\/span>\n\n$multiply = function<\/span> ($x, $y)<\/span> <\/span>{\n\treturn<\/span> $x * $y;\n};<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
And this calls the anonymous function via the $multiply<\/code> variable:<\/p>\n\n\n
<?php<\/span>\n\n$multiply = function<\/span> ($x, $y)<\/span> <\/span>{\n\treturn<\/span> $x * $y;\n};\n\necho<\/span> $multiply(10<\/span>, 20<\/span>);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
When you dump the information on the $multiply<\/code> variable, you’ll see that it’s actually a Clousure<\/code> object:<\/p>\n\n\n
<?php<\/span>\n\n$multiply = function<\/span> ($x, $y)<\/span> <\/span>{\n\treturn<\/span> $x * $y;\n};\n\nvar_dump($multiply);<\/span><\/code><\/span>Code language:<\/span> HTML, XML<\/span> (<\/span>xml<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
object(Closure)#1 (1) {<\/span>\n  [\"parameter\"<\/span>]=> array<\/span>(2<\/span>) {\n    [\"$x\"<\/span>]=>string(10<\/span>) \"<required>\"<\/span>\n    [\"$y\"<\/span>]=>string(10<\/span>) \"<required>\"<\/span>\n  }\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Since an anonymous function is an object, you can assign it to a variable<\/a>, pass it to a function, and return it from a function.<\/p>\n\n\n\n
Passing an anonymous function to another function #<\/a><\/h2>\n\n\n\n
PHP has many built-in functions that accept a callback function, for example, the array_map()<\/a><\/code> function.<\/p>\n\n\n\n
The array_map()<\/code> function accepts a callback function and an array. It applies the callback function to each element and includes the results in a new array.<\/p>\n\n\n\n
The following example shows how to double each number in an array:<\/p>\n\n\n
<?php<\/span> \n\nfunction<\/span> double_it<\/span>($element)<\/span>\n<\/span>{\n\treturn<\/span> $element * 2<\/span>;\n}\n\n$list = [10<\/span>, 20<\/span>, 30<\/span>];\n$double_list = array_map('double_it'<\/span>, $list);\n\nprint_r($double_list);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
How it works.<\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
Note that the Closure<\/code> in PHP is not the same as the closure in other programming languages such as JavaScript <\/a>or Python<\/a>.<\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
Try it<\/a><\/p>\n\n\n\n
To use an anonymous function, you need to assign it to a variable<\/a> and call the function via the variable.<\/p>\n\n\n\n