PHP's implicit handling of undefined array keys can lead to silent errors where accessing a non-existent key returns nothing rather than throwing an error. This makes debugging difficult.

PHP array access with non-numeric keys causing unexpected undefined offset errors. Illustrates the subtle difference between using foreach and direct numerical index access.

$ _POST or $ _GET are two special PHP functions that are used to get variables from a user-filled form. While using these functions, a user may encounter an error, stating that there is an undefined ...