length: Optional. Numeric value. Specifies the length of the returned array. If this value is set to a negative number, the function will stop slicing that far from the last element. If this value is ...

Following along with Video: PHP for Beginners Crash Course by Brad Traversy of Traversy Media. Link: https://youtu.be/BUCiSSyIGGU - BigSteveLittle/tma-php-for-beginners ...

You can utilize the string functions available in PHP to find instances of "field_" in your array. Here is something I whipped up to test this in action.