Python Calendar Module

The calendar module in Python provides functions for working with calendars, including generating calendar data for specific months or years, determining weekdays, and performing various calendar-related operations.

Importing the Module

python

import calendar

Key Methods in the Calendar Module

1. calendar.month(year, month, w=2, l=1)

Returns a multiline string with a calendar for the specified month.

Parameters:

• year: Year (e.g., 2024)
• month: Month (1-12)
• w: Width of date columns (default: 2)
• l: Number of lines per week (default: 1)

python

import calendar

# Display calendar for January 2024
print(calendar.month(2024, 1))

Output:

text

    January 2024
Mo Tu We Th Fr Sa Su
 1  2  3  4  5  6  7
 8  9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31

2. calendar.calendar(year, w=2, l=1, c=6, m=3)

Returns a multiline string with a calendar for the entire year.

Parameters:

• year: Year
• w: Width of date columns
• l: Number of lines per week
• c: Number of spaces between months
• m: Number of months per row

python

import calendar

# Display entire year 2024 (first 3 months)
print(calendar.calendar(2024, m=3)[:1000])  # Showing first 1000 characters

3. calendar.isleap(year)

Returns True if the year is a leap year, False otherwise.

python

import calendar

print(calendar.isleap(2024))  # True
print(calendar.isleap(2023))  # False
print(calendar.isleap(2000))  # True
print(calendar.isleap(1900))  # False

4. calendar.leapdays(y1, y2)

Returns the number of leap years between years y1 and y2 (exclusive).

python

import calendar

print(calendar.leapdays(2000, 2024))  # 6 leap years (2000, 2004, 2008, 2012, 2016, 2020)

5. calendar.weekday(year, month, day)

Returns the day of the week as an integer (0=Monday, 6=Sunday).

python

import calendar

# Check what day January 1, 2024 falls on
day_index = calendar.weekday(2024, 1, 1)
print(f"Day index: {day_index}")  # 0 (Monday)

# Convert to day name
days = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
print(f"January 1, 2024 was a {days[day_index]}")

6. calendar.monthrange(year, month)

Returns a tuple (weekday_of_first_day, number_of_days) for the specified month.

python

import calendar

# Get information about February 2024
first_day, num_days = calendar.monthrange(2024, 2)
print(f"First day index: {first_day}")  # 3 (Thursday)
print(f"Number of days: {num_days}")    # 29 (leap year)

7. calendar.monthcalendar(year, month)

Returns a matrix representing a month’s calendar.

python

import calendar

# Get February 2024 as a matrix
feb_2024 = calendar.monthcalendar(2024, 2)
print("February 2024 matrix:")
for week in feb_2024:
    print(week)

Output:

text

February 2024 matrix:
[0, 0, 0, 1, 2, 3, 4]
[5, 6, 7, 8, 9, 10, 11]
[12, 13, 14, 15, 16, 17, 18]
[19, 20, 21, 22, 23, 24, 25]
[26, 27, 28, 29, 0, 0, 0]

8. calendar.day_name and calendar.day_abbr

Lists of full and abbreviated day names.

python

import calendar

print("Full day names:")
for day in calendar.day_name:
    print(day)

print("\nAbbreviated day names:")
for day in calendar.day_abbr:
    print(day)

Output:

text

Full day names:
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday

Abbreviated day names:
Mon
Tue
Wed
Thu
Fri
Sat
Sun

9. calendar.month_name and calendar.month_abbr

Lists of full and abbreviated month names.

python

import calendar

print("Full month names:")
for i, month in enumerate(calendar.month_name):
    print(f"{i}: {month}")

print("\nAbbreviated month names:")
for i, month in enumerate(calendar.month_abbr):
    print(f"{i}: {month}")

Practical Examples

Example 1: Check if a date is a weekend

python

import calendar

def is_weekend(year, month, day):
    day_index = calendar.weekday(year, month, day)
    return day_index >= 5  # 5=Saturday, 6=Sunday

print(is_weekend(2024, 1, 6))   # True (Saturday)
print(is_weekend(2024, 1, 7))   # True (Sunday)
print(is_weekend(2024, 1, 8))   # False (Monday)

Example 2: Get all Fridays in a month

python

import calendar

def get_fridays(year, month):
    fridays = []
    cal = calendar.monthcalendar(year, month)
    for week in cal:
        if week[4] != 0:  # Friday is index 4
            fridays.append(week[4])
    return fridays

fridays_jan_2024 = get_fridays(2024, 1)
print(f"Fridays in January 2024: {fridays_jan_2024}")

Example 3: Custom calendar formatting

python

import calendar

def custom_calendar(year, month):
    # Set first weekday to Sunday (0=Monday, 6=Sunday by default)
    calendar.setfirstweekday(calendar.SUNDAY)
    
    # Create calendar with custom width
    cal_text = calendar.month(year, month, w=4)
    return cal_text

print(custom_calendar(2024, 12))

Example 4: Count working days in a month

python

import calendar

def count_working_days(year, month):
    first_day, num_days = calendar.monthrange(year, month)
    working_days = 0
    
    for day in range(1, num_days + 1):
        weekday = calendar.weekday(year, month, day)
        if weekday < 5:  # Monday to Friday
            working_days += 1
    
    return working_days

work_days_jan = count_working_days(2024, 1)
print(f"Working days in January 2024: {work_days_jan}")

Setting the First Day of the Week

By default, Monday is the first day of the week. You can change this:

python

import calendar

# Set Sunday as first day of week
calendar.setfirstweekday(calendar.SUNDAY)

# Or use integer (6 for Sunday)
calendar.setfirstweekday(6)

# Get current first weekday
print(f"First weekday: {calendar.firstweekday()}")  # Returns 6 for Sunday

The calendar module is particularly useful for applications that need to generate calendar views, calculate dates, or work with scheduling systems.