PHP array_map() Sample Code and Explanation

In PHP, the array_map() function is a powerful tool for manipulating arrays. It takes an array and a callback function as parameters, applies the callback function to each element of the array, and returns a new array with the modified values.

Basic Usage

Here’s a simple example of using array_map():

<?php
function square($n) {
  return $n * $n;
}

$numbers = array(1, 2, 3, 4, 5);

$squares = array_map("square", $numbers);

print_r($squares);
?>

In this example, we define a function called square() that takes a number and returns its square. We then create an array of numbers and pass it to array_map() along with the square() function as the callback.

array_map() applies the square() function to each element of the array and returns a new array with the squared values. The output of the above code would be:

Array
(
    [0] => 1
    [1] => 4
    [2] => 9
    [3] => 16
    [4] => 25
)

Multiple Arrays

array_map() can also take multiple arrays as input. Here’s an example:

<?php
function add($a, $b) {
  return $a + $b;
}

$a = array(1, 2, 3);
$b = array(4, 5, 6);

$c = array_map("add", $a, $b);

print_r($c);
?>

In this example, we define a function called add() that takes two numbers and returns their sum. We then create two arrays of numbers and pass them to array_map() along with the add() function as the callback.

array_map() applies the add() function to each corresponding element of the arrays and returns a new array with the summed values. The output of the above code would be:

Array
(
    [0] => 5
    [1] => 7
    [2] => 9
)

Using Anonymous Functions

In some cases, it may be more convenient to use anonymous functions (also known as closures) instead of named functions. Here’s an example:

<?php
$numbers = array(1, 2, 3, 4, 5);

$squares = array_map(function($n) { return $n * $n; }, $numbers);

print_r($squares);
?>

In this example, we create an anonymous function that takes a number and returns its square. We then pass the anonymous function to array_map() instead of a named function.

array_map() applies the anonymous function to each element of the array and returns a new array with the squared values. The output of the above code would be the same as the first example:

Array
(
    [0] => 1
    [1] => 4
    [2] => 9
    [3] => 16
    [4] => 25
)

Conclusion

The array_map() function is a powerful tool for manipulating arrays in PHP. It allows you to apply a callback function to each element of an array and return a new array with the modified values. With the ability to take multiple arrays as input and use anonymous functions, array_map() is a versatile function that you’ll find yourself using frequently.

We hope this article has been helpful in explaining how array_map() works and giving you some ideas for how you can use it in your own code. Happy coding!