Python calendar module

Python contains an inbuilt module known as the calendar module for handling operations relating to calendars. The calendar module gives calendars as outputs and also includes other programs and codes involving calendars. All the functions and classes within the calendar module make use of the standard Gregorian calendar. As a default setting these calendars have Monday as the first day of the week and Sunday as the last.

What is python calendar module?

Python calendar module allows you to work with calendars and perform functions on calendars. The calendar by default starts on Monday(=0) and ends on Sunday(=6).

In this tutorial, we are using the Gregorian calendar that extends infinitely in both ways. The ISO declares how to interrupt zero and negative years. Year 0 is ‘1 BC’, year-1 is ‘2 BC’ and so on.

Import the calendar module using the following command

Import calendar as cd

Python calendar class

The constructor for the calendar class is as follows:

class calendar.Calendar(firstweekday=0)

This creates an object of the calendar and begins at the day we decide. By default it begins on Monday which is set to 0.

Work with the calendar module

Step 1: execute the code

Type the following code in your editor and click run to execute the results.

import calendar
c=calendar.TextCalendar(calendar.SUNDAY)
str=c.formatmonth(2025,1)
print(str)

This prints the calendar of January month of 2025.

• In the first line, we are importing in the calendar library without which it is impossible to execute the code easily.
• In the second line, we are telling the interpreter to create a text calendar
• In the third line, we are creating a calendar for the year 2025 and the month of January
• Print str command prints the calendar as output

Step 2:

We can also print the calendar in HTML format, this feature is very helpful to the developers in case they want to make edits to the look of the calendar. You can edit the data inside the HTML file if you need.

import calendar
hc=calendar.HTMLCalendar(calendar.THURSDAY)
str=hc.formatmonth(2025,1)
print(str)

This prints the calendar of January month of 2025 in HTML format.

Step 3:

c.itermonthday(2025, 4) allows you to loop through the days. It returns the total number of days in the month.

You can also get data from your personal local systems, such as months or weekdays

import calendar 
for name in calendar.month_name:
    print(name)

This gives names of all months in the output.

Step 4:

You can get the list of the specific day for the entire year. Consider the example where there is an audit day on the monday of every week. You can use this code to get date for each first monday of the month:

import calendar 
for month in range (1,13):
    mycalen=calendar.monthcalendar(2022, month)
    week1=mycalen[0]
    week2=mycalen[1]
    if week1[calendar.MONDAY]!=0:
        auditday=week1[calendar.MONDAY]
    else:
        auditday=week2[calendar.MONDAY]
    print("%10s %2d" % (calendar.month_name[month],auditday))

Output:

Let us look at few other sample codes

Example 1

Display calendar of the given month:

Import calendar
yy=2017
mm=11
print(calendar.month(yy,mm))

In the above piece of code, we import the calendar module and declare the year and month of which we want to print the calendar. It gives calendar of November month of 2017.

Example 2

Display calendar of any given year:

Import calendar
print(calendar.calendar(2022,2,1,6))

It displays calendar of 2022.

See the days of the week

weekheader() method allows you to print the days of the week and it begins with monday by default.

You can give a header argument to the weekheader() method. This integer tells the number or length of the string

import calendar
print(calendar.weekheader(4))

Output:

setfirstweekday() method allows you to change the default Monday to a weekday fo your choice.

See if a year is leap year or not

Let us write a code to check if the given year is a leap year or not. The isleap() method allows you to check this. We can pass the year as an argument and the code prints true or false accordingly.

import calendar
print(calendar.isleap(2023))

Output:

Check the number of leap days between a specific range of years

leapdays() method to check the number of leap days between to different years that we pass as arguments of the method.

import calendar
checkleap= calendar.leapdays(2020, 2024)
print(checkleap)

Output:

Class calendar.calendar(firstweekday=0)

This creates a calendar object. The firstweekday is an integer indicating the first day of the week. Monday is 0 and Sunday is 6.

A calendar object contains many methods for calendar data formatting. The subclasses format the calendars.

Class calendar.Textcalendar

This class generates plain text calendars. The constructor for this class has the following syntax:

class calendar.Textcalendar(firstweekday=0)

It has the following methods:

Examples of the method in the TextCalendar class:

1. formatmonth(theyear, themonth, w=0, L=0)

We obtain the calendar of the month in the form of a multiline string. W is the width of the centred date columns, l is the number of lines each week can use. We need to give the value of the first weekday

import calendar as cd
t=cd.TextCalendar(0)
print(t.formatmonth(2018,12))

Output:

2. prmonth(theyear, themonth, [w=0,l=0]

The above code can simply also be done with the prmonth() method

import calendar as cd
t=cd.TextCalendar(0)
t.prmonth(2018,12)

Output
December 2018
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

3. formatyear(theyear, [w=2, l=1, c=6, m=3])

This gives the calendar for an entire year. W stands for width, l stands for lines per week, c stands for the number of spaces between month columns. We need to specify firstweekday.

import calendar as cd
t=cd.TextCalendar(0)
print(t.formatyear(2018,5)) #sets w=5 and m is 3 by default
print(t.formatyear(2018,m=5))

4. pryear(theyear, [w=2, l=1, c=, m=3])

Prints the whole year calendar same as above

import calendar as cd
t=cd.TextCalendar(0)
t.pryear(2018,m=5)

Class calendar.HTMLcalendar

This class creates HTML calendars. The syntax for the constructor is as follows:

Class calendar.HTMLCalendar(firstweekday=0)

1. formatmonth(theyear, themonth, withyear=True)

This method prints the calendar for the month in HTML table format

import calendar as cd
h=cd.HTMLCalendar()
print(h.formatmonth(2018,12))

Output:

2. formatyear(theyear, width=3)

Prints the HTML table for the complete year calendar. The width specifies the number of months in a row and by default it is 3.

import calendar as cd
h=cd.HTMLCalendar()
print(h.formatyear(2018,3))

3. formatyearpage(theyear, width=3, css=’calendar.css’, encoding=None)

Prints the calendar for the whole year as an HTML page and the default width is set to 3. If we do not make use of the css file we can type none instead.

import calendar as cd
h=cd.HTMLCalendar()
print(h.formatyearpage(2020,css=None))

It contains the following methods:

Simple TextCalendar class:

For building simple text calendars, the calendar module offers the following functions:

Conclusion

In this article we look briefly into the Python calendar module. We look at some of its important classes and their prominent methods. We hope our explanation was easy to understand.