What are the best practices for handling undefined variables in PHP code?

When handling undefined variables in PHP code, it is important to first check if the variable is set using isset() or empty() functions to avoid PHP notices or warnings. If the variable is not set, you can assign a default value to it using the ternary operator or the ?? null coalescing operator. This helps prevent unexpected behavior or errors in your code. 

// Check if the variable is set and assign a default value if not
$variable = isset($undefinedVariable) ? $undefinedVariable : 'default value';

// Using the null coalescing operator
$variable = $undefinedVariable ?? 'default value';

Keywords

error handling isset function null coalescing operator strict typing debugging

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