How to access the Variable in inner function PHP?

Question

How to access the variable in inner function of outer function variable?

I want to access $arr variable in the inner function.

<?php

function outer() {

    $arr = array();

    function inner($val) {

        global $arr;

        if($val > 0) {
            array_push($arr,$val);
        }
    }

    inner(0);
    inner(10);
    inner(20);

    print_r($arr);

}

outer();

codepad link

Answer 1

This kind of "inner function" does not do what you probably expect. The global(!) function inner() will be defined upon calling outer(). This also means, calling outer() twice results in a "cannot redefine inner()" error.

As @hindmost pointed out, you need closures, functions that can get access to variables of the current scope. Also, while normal functions cannot have a local scope, closures can, because they are stored as variables.

Your code with Closures:

function outer() {

    $arr = array();

    $inner = function($val) use (&$arr) {
        if($val > 0) {
            array_push($arr,$val);
        }
    }

    $inner(0);
    $inner(10);
    $inner(20);

    print_r($arr);

}

outer();