What are common pitfalls when managing variables in PHP files?

Common pitfalls when managing variables in PHP files include using undefined variables, not properly sanitizing user input, and not properly scoping variables. To solve these issues, always initialize variables before using them, validate and sanitize user input to prevent security vulnerabilities, and use appropriate scoping to avoid conflicts between variables. 

// Initializing variables before using them
$name = "";
$email = "";

// Validating and sanitizing user input
$name = isset($_POST['name']) ? htmlspecialchars($_POST['name']) : "";
$email = isset($_POST['email']) ? filter_var($_POST['email'], FILTER_SANITIZE_EMAIL) : "";

// Properly scoping variables
function exampleFunction() {
    $localVariable = "This is a local variable";
    return $localVariable;
}

Keywords

variable scope global keyword variable naming conventions variable manipulation variable initialization

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