What is the best practice for checking if a variable exists in PHP?

When checking if a variable exists in PHP, it's best practice to use the isset() function. This function checks if a variable is set and is not NULL. Using isset() helps prevent PHP errors that may occur when trying to access a variable that hasn't been defined. 

// Check if a variable named $myVar exists
if (isset($myVar)) {
    echo '$myVar exists!';
} else {
    echo '$myVar does not exist.';
}

Keywords

isset empty variable validation conditional

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