How to fix 'Warning: array_key_exists(): The First Argument Should Be Either a String or an Integer' error in PHP

This article delves into exploring the causes and solutions for a PHP error that can potentially manifest while working on an application using the PHP language, specifically the 'Warning: array_key_exists(): The First Argument Should Be Either a String or an Integer' error. If you happen to encounter this error, this article aims to assist you in addressing it. I will provide some code snippets that simulate the error scenario and provide resolutions to correct or prevent it.