How can the use of double quotes or single quotes in PHP arrays like $_POST affect error reporting and variable assignment in form processing scripts?

Using double quotes or single quotes in PHP arrays like $_POST can affect error reporting and variable assignment in form processing scripts because if the array key is enclosed in double quotes, PHP will try to interpret it as a variable. This can lead to unexpected behavior and potential security vulnerabilities. To avoid this issue, always use single quotes when accessing array keys in $_POST to ensure correct variable assignment and prevent potential errors.

// Incorrect way using double quotes
$value = $_POST["key"];

// Correct way using single quotes
$value = $_POST['key'];