PHP – function use

As with the previous post about the use method within php (here), you are also able to use the use method attached to a callable function as in

function ($parameter) USE ($somevalue)

So you are able to use any variables that are within scope within the new function, below is an example where I am using the array walk methods callback (which means call a function that is available). The function is using the values within the array ($arrays 4 and 5) and adding them to the $value variable that is passed within the use parameters (here I am using the & symbol which means to pass in reference and not just a copy of the value (you are able to alter the actual parameter passed), so in this instance the $value starts of with 1, then adds 4 and then 5 to it which in turn the result is 10.

$value = 1;
$callback = function ($one) use (&$value) {
	$value += $one;
$arrays = array(4,5);
array_walk($arrays, $callback);
print_r("value : " .$value);

And the output would be.

value : 10