Python
import calendar

# Print a text calendar for a month
print(calendar.month(2024, 3))

# Print a full year calendar
print(calendar.calendar(2024))

# Check leap year
calendar.isleap(2024)  # True

# Get weekday of a specific date (0=Monday)
calendar.weekday(2024, 3, 15)  # Friday -> 4

# Get (first_weekday, number_of_days) for a month
calendar.monthrange(2024, 2)  # (3, 29) -> Feb 2024 starts Thu, has 29 days

Progress:

• Step 1: Decide output format needed (text, HTML, or raw data structures)
• Step 2: Choose the right class/function (Calendar, TextCalendar, HTMLCalendar, or module-level convenience functions)
• Step 3: Set locale/first-weekday if non-default behavior required
• Step 4: Generate data (iterators for weeks/months/years, or formatted strings)
• Step 5: Post-process output (e.g., strip empty days marked 0, style HTML)

Choosing the right tool

• Quick print/debug → calendar.month(year, month), calendar.calendar(year)
• Iterate raw day numbers (0 = day outside month) → Calendar.itermonthdays()
• Iterate (day, weekday) tuples → Calendar.itermonthdays2()
• Iterate actual datetime.date objects → Calendar.itermonthdates() (note: can spill into adjacent years at Dec/Jan boundaries)
• Group days into weeks → Calendar.monthdayscalendar() / monthdatescalendar()
• HTML output → HTMLCalendar class, formatmonth()/formatyear()
• Locale-specific names → LocaleTextCalendar / LocaleHTMLCalendar

Setting the first day of the week

Python
c = calendar.Calendar(firstweekday=6)  # Sunday-first
calendar.setfirstweekday(calendar.SUNDAY)  # affects module-level functions globally

Default is Monday (0). Constants: MONDAY=0 ... SUNDAY=6.

Example 1: Get weeks of a month as date objects

Input:

Python
import calendar
cal = calendar.Calendar()
list(cal.monthdatescalendar(2024, 2))

Output:

Python
[[datetime.date(2024, 1, 29), ..., datetime.date(2024, 2, 4)],
 [datetime.date(2024, 2, 5), ..., datetime.date(2024, 2, 11)],
 ...
 [datetime.date(2024, 2, 26), ..., datetime.date(2024, 3, 3)]]

Each inner list has exactly 7 dates; padding days come from adjacent months.

Example 2: Generate an HTML calendar for a month

Input:

Python
import calendar
hc = calendar.HTMLCalendar(firstweekday=calendar.SUNDAY)
html = hc.formatmonth(2024, 12)

Output: A string of <table class="month">...</table> HTML with <td class="mon">, <td class="noday"> for padding cells, etc. — ready to embed in a page or style with CSS classes (month, year, noday, mon, tue, ... , sun).

Example 3: Count weekday occurrences in a month

Input:

Python
calendar.monthrange(2024, 2)

Output:

Python
(3, 29)  # Feb 2024 starts on a Thursday (index 3), has 29 days

Use this to compute how many Mondays/Fridays/etc. occur in a month without iterating.