Python Build a Monthly Calendar Generator

Print a calendar month with a chosen first weekday.

How It Works

A simple month generator accepts a year and month, validates the input with calendar.monthrange, and formats it with TextCalendar. Keep the formatting and input validation separate for easy testing.

Step-by-Step Example

import calendar
def make_calendar(year, month):
    calendar.monthrange(year, month)
    return calendar.TextCalendar(firstweekday=calendar.MONDAY).formatmonth(year, month)
print('October' in make_calendar(2026, 10))

Understanding the Example

The function definition gives the operation a reusable name and makes its inputs explicit.
The print() call exposes the result so you can compare it with the behavior described above. Check the value and its type when experimenting.

A successful run of this example prints the following output:

True

Where This Fits in a Real Program

For event timestamps, distinguish the displayed local clock from the instant that it represents. Store or exchange an unambiguous aware value, then convert it when displaying it to a user. For repeated calendar appointments, use a geographic timezone so daylight-saving rules are not lost.

Practice: Try It Yourself

A pure string-returning function is easier to test than one that prints directly.

For this exercise, predict the result before running the changed code. Then explain the difference between the original and modified cases using the actual values, not just whether the program completed.

Common Beginner Mistakes

Skipping validation and allowing impossible month numbers into the generator.
Extend the function to create a saved yearly calendar.

Key Takeaways

Print a calendar month with a chosen first weekday.
A simple month generator accepts a year and month, validates the input with calendar.monthrange, and formats it with TextCalendar.
Apply the demonstrated operation to the practice input and verify its result before depending on it in a larger program.