What is the difference between using OR and XOR operators in checking variable existence in PHP?

When checking variable existence in PHP, using the OR operator (||) will return true if either variable is set, while the XOR operator (^) will return true only if one variable is set but not both. If you want to check if either variable is set, use the OR operator. If you want to check if only one variable is set but not both, use the XOR operator.

// Using OR operator to check if either variable is set
if(isset($variable1) || isset($variable2)) {
    // Code to execute if either variable is set
}

// Using XOR operator to check if only one variable is set but not both
if((isset($variable1) && !isset($variable2)) || (!isset($variable1) && isset($variable2)) {
    // Code to execute if only one variable is set but not both
}