Unexpected `array_reduce` Behavior with Multidimensional Arrays in PHP 8.1
I've looked through the documentation and I'm still confused about I'm refactoring my project and I'm stuck on something that should probably be simple... I'm stuck on something that should probably be simple... I tried several approaches but none seem to work. I'm working with an scenario when using `array_reduce` to sum values from a multidimensional array in PHP 8.1. I have a nested array that contains multiple categories, each with an array of items having a `price` key. Here's the structure of my data: ```php $data = [ 'fruits' => [ ['name' => 'apple', 'price' => 1.5], ['name' => 'banana', 'price' => 1.0], ], 'vegetables' => [ ['name' => 'carrot', 'price' => 0.8], ['name' => 'lettuce', 'price' => 1.2], ], ]; ``` I want to calculate the total price of all items across all categories using `array_reduce`. My current implementation looks like this: ```php $totalPrice = array_reduce($data, function ($carry, $category) { return $carry + array_reduce($category, function ($sum, $item) { return $sum + $item['price']; }, 0); }, 0); ``` However, I'm getting an unexpected result. Instead of getting the total price as 4.5, I receive a warning: `Warning: array_reduce(): Argument #1 ($array) must be of type array, null given`. I suspect it has something to do with how I'm handling the nested arrays, but I'm not sure how to fix it. I also tried using `foreach` to iterate over the items, but I really want to leverage `array_reduce` for this task. Can anyone point out what might be going wrong or suggest a better approach to achieve this? Thanks! Am I missing something obvious? Is there a better approach? My development environment is macOS. How would you solve this? What's the best practice here? This is for a application running on CentOS. Any examples would be super helpful.