Unexpected Output from array_map() with Callback in PHP 8.1: Closure Binding guide
I'm writing unit tests and Can someone help me understand I'm stuck on something that should probably be simple....... I'm relatively new to this, so bear with me... I'm working with an unexpected output when trying to use `array_map()` with a closure in PHP 8.1. Specifically, I have a simple array of strings that I want to transform to uppercase using a callback function, but the output is not what I expect. Here’s my code: ```php $array = ['apple', 'banana', 'cherry']; $callback = function($item) { return strtoupper($item); }; $uppercasedArray = array_map($callback, $array); print_r($uppercasedArray); ``` When I run this code, I expect the output to be `Array ( [0] => APPLE [1] => BANANA [2] => CHERRY )`, but instead, I'm getting `Array ( [0] => [1] => [2] => )`. I have checked to ensure that the array is indeed populated before passing it to `array_map()`, and it prints correctly if I use a simple loop to apply `strtoupper()` directly: ```php foreach ($array as $item) { echo strtoupper($item) . "\n"; } ``` This outputs the expected uppercase letters. I've also tried to use an anonymous function assigned to a variable, and I’ve ensured that there are no errors or notices being thrown. Additionally, I confirmed that the PHP version I’m using is indeed 8.1.0. Is there something specific about closure binding in PHP 8.1 that could be causing this behavior? I would appreciate any suggestions or insights on what might be going wrong here. This is part of a larger web app I'm building. I'd really appreciate any guidance on this. Has anyone dealt with something similar? I appreciate any insights! Any examples would be super helpful.