How can the use of isset() function in PHP help prevent undefined variable notices?

When accessing variables in PHP, it is common to encounter undefined variable notices if the variable has not been set or initialized. This can lead to errors and unexpected behavior in the code. By using the isset() function in PHP, we can check if a variable is set before trying to access it, thus preventing undefined variable notices.

// Check if the variable is set before accessing it
if(isset($variable)){
    // Variable is set, now it can be safely used
    echo $variable;
} else {
    // Variable is not set
    echo "Variable is not set.";
}