What potential pitfalls should be avoided when using PHP to interpret new variables?

When interpreting new variables in PHP, it is important to avoid potential pitfalls such as injection attacks or unexpected variable conflicts. To prevent injection attacks, always sanitize user input before assigning it to a variable. Additionally, be cautious when naming variables to avoid conflicts with existing variables or reserved keywords.

// Sanitize user input before assigning it to a variable
$newVariable = filter_var($_POST['input'], FILTER_SANITIZE_STRING);

// Avoid conflicts with existing variables or reserved keywords by using unique variable names
$newVariable = "example";