In what ways can PHP developers ensure the flexibility and maintainability of automated scripts by storing holiday dates in external files for dynamic checking within the code?

By storing holiday dates in external files, PHP developers can ensure flexibility and maintainability of automated scripts by easily updating holiday dates without modifying the code. This allows for dynamic checking within the code to determine if a given date is a holiday, making the script more adaptable to changes in holiday schedules.

// Load holiday dates from an external file
$holidays = file('holiday_dates.txt', FILE_IGNORE_NEW_LINES);

// Check if a given date is a holiday
$date = '2022-12-25';
if (in_array($date, $holidays)) {
    echo "The date $date is a holiday.";
} else {
    echo "The date $date is not a holiday.";
}