Master PHP’s array_map(): Transform Arrays with Simple Callbacks

In PHP's function library, the array_map() function is a powerful tool that applies a callback to each element of an array and returns a new array.

1. Basic usage of array_map()

The basic syntax is: array_map(callable $callback, array ...$arr) The $callback parameter is the function to be called for each element, and $arr represents the array(s) to process. Multiple arrays can be passed.

Example:

$arr = [1, 2, 3];
$newArr = array_map(function($v) {
    return $v * 2;
}, $arr);
print_r($newArr);

Output:

Array ( [0] => 2 [1] => 4 [2] => 6 )

2. Advanced usage of array_map()

array_map()

can handle multiple arrays and pass additional parameters to the callback.

Example with two arrays:

$arr1 = [1, 2, 3];
$arr2 = [4, 5, 6];
$newArr = array_map(function($v1, $v2) {
    return $v1 + $v2;
}, $arr1, $arr2);
print_r($newArr);

Result: Array ( [0] => 5 [1] => 7 [2] => 9 ) Example passing extra parameter:

$arr = [1, 2, 3];
$prefix = 'num:';
$newArr = array_map(function($v, $prefix) {
    return $prefix . $v;
}, $arr, array_fill(0, count($arr), $prefix));
print_r($newArr);

Result:

Array ( [0] => num:1 [1] => num:2 [2] => num:3 )

Conclusion

The array_map() function simplifies array processing in PHP. By providing appropriate callbacks and parameters, you can perform a wide range of transformations. Pay attention to the number of arguments and callback logic to achieve the desired results.