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calendar — General calendar-related functions¶
Source code: Lib/calendar.py
This module allows you to output calendars like the Unix cal program,
and provides additional useful functions related to the calendar. By default,
these calendars have Monday as the first day of the week, and Sunday as the last
(the European convention). Use setfirstweekday() to set the first day of
the week to Sunday (6) or to any other weekday. Parameters that specify dates
are given as integers. For related
functionality, see also the datetime and time modules.
The functions and classes defined in this module
use an idealized calendar, the current Gregorian calendar extended indefinitely
in both directions. This matches the definition of the “proleptic Gregorian”
calendar in Dershowitz and Reingold’s book “Calendrical Calculations”, where
it’s the base calendar for all computations. Zero and negative years are
interpreted as prescribed by the ISO 8601 standard. Year 0 is 1 BC, year -1 is
2 BC, and so on.
-
class calendar.Calendar(firstweekday=0)¶
Creates a Calendar object. firstweekday is an integer specifying the
first day of the week. MONDAY is 0 (the default), SUNDAY is 6.
A Calendar object provides several methods that can be used for
preparing the calendar data for formatting. This class doesn’t do any formatting
itself. This is the job of subclasses.
Calendar instances have the following methods and attributes:
-
firstweekday¶
The first weekday as an integer (0–6).
This property can also be set and read using
setfirstweekday() and
getfirstweekday() respectively.
-
getfirstweekday()¶
Return an int for the current first weekday (0–6).
Identical to reading the firstweekday property.
-
setfirstweekday(firstweekday)¶
Set the first weekday to firstweekday, passed as an int (0–6).
Identical to setting the firstweekday property.
-
iterweekdays()¶
Return an iterator for the weekday numbers that will be used for one
week. The first value from the iterator will be the same as the value of
the firstweekday property.
-
itermonthdates(year, month)¶
Return an iterator for the month month (1–12) in the year year. This
iterator will return all days (as datetime.date objects) for the
month and all days before the start of the month or after the end of the
month that are required to get a complete week.
-
itermonthdays(year, month)¶
Return an iterator for the month month in the year year similar to
itermonthdates(), but not restricted by the datetime.date
range. Days returned will simply be day of the month numbers. For the
days outside of the specified month, the day number is 0.
-
itermonthdays2(year, month)¶
Return an iterator for the month month in the year year similar to
itermonthdates(), but not restricted by the datetime.date
range. Days returned will be tuples consisting of a day of the month
number and a weekday number.
-
itermonthdays3(year, month)¶
Return an iterator for the month month in the year year similar to
itermonthdates(), but not restricted by the datetime.date
range. Days returned will be tuples consisting of a year, a month and a day
of the month numbers.
-
itermonthdays4(year, month)¶
Return an iterator for the month month in the year year similar to
itermonthdates(), but not restricted by the datetime.date
range. Days returned will be tuples consisting of a year, a month, a day
of the month, and a day of the week numbers.
-
monthdatescalendar(year, month)¶
Return a list of the weeks in the month month of the year as full
weeks. Weeks are lists of seven datetime.date objects.
-
monthdays2calendar(year, month)¶
Return a list of the weeks in the month month of the year as full
weeks. Weeks are lists of seven tuples of day numbers and weekday
numbers.
-
monthdayscalendar(year, month)¶
Return a list of the weeks in the month month of the year as full
weeks. Weeks are lists of seven day numbers.
-
yeardatescalendar(year, width=3)¶
Return the data for the specified year ready for formatting. The return
value is a list of month rows. Each month row contains up to width
months (defaulting to 3). Each month contains between 4 and 6 weeks and
each week contains 1–7 days. Days are datetime.date objects.
-
yeardays2calendar(year, width=3)¶
Return the data for the specified year ready for formatting (similar to
yeardatescalendar()). Entries in the week lists are tuples of day
numbers and weekday numbers. Day numbers outside this month are zero.
-
yeardayscalendar(year, width=3)¶
Return the data for the specified year ready for formatting (similar to
yeardatescalendar()). Entries in the week lists are day numbers. Day
numbers outside this month are zero.
-
class calendar.TextCalendar(firstweekday=0)¶
This class can be used to generate plain text calendars.
TextCalendar instances have the following methods:
-
prweek(theweek, width)¶
Print a week’s calendar as returned by formatweek() and without a
final newline.
-
formatday(day, weekday, width)¶
Return a string representing a single day formatted with the given width.
If day is 0, return a string of spaces of
the specified width, representing an empty day. The weekday parameter
is unused.
-
formatweek(theweek, width)¶
Return a single week in a string with no newline. width specifies
the width of the date columns, which are centered. Depends
on the first weekday as specified in the constructor or set by the
setfirstweekday() method.
-
formatweekday(day, width)¶
Return a string representing the name of a single weekday formatted to
the specified width. The day parameter is an integer representing
the day of the week, where 0 is Monday and 6 is Sunday.
-
formatweekheader(width)¶
Return a string containing the header row of weekday names, formatted
with the given width for each column. The names depend on the locale
settings and are padded to the specified width.
-
formatmonth(theyear, themonth, w=0, l=0)¶
Return a month’s calendar in a multi-line string. If w is provided, it
specifies the width of the date columns, which are centered. If l is
given, it specifies the number of lines that each week will use. Depends
on the first weekday as specified in the constructor or set by the
setfirstweekday() method.
-
formatmonthname(theyear, themonth, width, withyear=True)¶
Return a string representing the month’s name centered within the
specified width. If withyear is True, include the year in the
output. The theyear and themonth parameters specify the year
and month for the name to be formatted respectively.
-
prmonth(theyear, themonth, w=0, l=0)¶
Print a month’s calendar as returned by formatmonth().
-
formatyear(theyear, w=2, l=1, c=6, m=3)¶
Return a m-column calendar for an entire year as a multi-line string.
Optional parameters w, l, and c are for date column width, lines per
week, and number of spaces between month columns, respectively. Depends on
the first weekday as specified in the constructor or set by the
setfirstweekday() method. The earliest year for which a calendar
can be generated is platform-dependent.
-
pryear(theyear, w=2, l=1, c=6, m=3)¶
Print the calendar for an entire year as returned by formatyear().
-
class calendar.HTMLCalendar(firstweekday=0)¶
This class can be used to generate HTML calendars.
HTMLCalendar instances have the following methods:
-
formatmonth(theyear, themonth, withyear=True)¶
Return a month’s calendar as an HTML table. If withyear is true the year
will be included in the header, otherwise just the month name will be
used.
-
formatyear(theyear, width=3)¶
Return a year’s calendar as an HTML table. width (defaulting to 3)
specifies the number of months per row.
-
formatyearpage(theyear, width=3, css='calendar.css', encoding=None)¶
Return a year’s calendar as a complete HTML page. width (defaulting to
3) specifies the number of months per row. css is the name for the
cascading style sheet to be used. None can be passed if no style
sheet should be used. encoding specifies the encoding to be used for the
output (defaulting to 'utf-8').
-
formatmonthname(theyear, themonth, withyear=True)¶
Return a month name as an HTML table row. If withyear is true the year
will be included in the row, otherwise just the month name will be
used.
HTMLCalendar has the following attributes you can override to
customize the CSS classes used by the calendar:
-
cssclasses¶
A list of CSS classes used for each weekday. The default class list is:
cssclasses = ["mon", "tue", "wed", "thu", "fri", "sat", "sun"]
more styles can be added for each day:
cssclasses = ["mon text-bold", "tue", "wed", "thu", "fri", "sat", "sun red"]
Note that the length of this list must be seven items.
-
cssclass_noday¶
The CSS class for a weekday occurring in the previous or coming month.
-
cssclasses_weekday_head¶
A list of CSS classes used for weekday names in the header row.
The default is the same as cssclasses.
-
cssclass_month_head¶
The month’s head CSS class (used by formatmonthname()).
The default value is "month".
-
cssclass_month¶
The CSS class for the whole month’s table (used by formatmonth()).
The default value is "month".
-
cssclass_year¶
The CSS class for the whole year’s table of tables (used by
formatyear()). The default value is "year".
-
cssclass_year_head¶
The CSS class for the table head for the whole year (used by
formatyear()). The default value is "year".
Note that although the naming for the above described class attributes is
singular (e.g. cssclass_month cssclass_noday), one can replace the
single CSS class with a space separated list of CSS classes, for example:
Here is an example how HTMLCalendar can be customized:
class CustomHTMLCal(calendar.HTMLCalendar):
cssclasses = [style + " text-nowrap" for style in
calendar.HTMLCalendar.cssclasses]
cssclass_month_head = "text-center month-head"
cssclass_month = "text-center month"
cssclass_year = "text-italic lead"
-
class calendar.LocaleTextCalendar(firstweekday=0, locale=None)¶
This subclass of TextCalendar can be passed a locale name in the
constructor and will return month and weekday names in the specified locale.
-
class calendar.LocaleHTMLCalendar(firstweekday=0, locale=None)¶
This subclass of HTMLCalendar can be passed a locale name in the
constructor and will return month and weekday names in the specified
locale.
Note
The constructor, formatweekday() and formatmonthname() methods
of these two classes temporarily change the LC_TIME locale to the given
locale. Because the current locale is a process-wide setting, they are
not thread-safe.
For simple text calendars this module provides the following functions.
-
calendar.setfirstweekday(firstweekday)¶
Sets the weekday (0 is Monday, 6 is Sunday) to start each week. The
values MONDAY, TUESDAY, WEDNESDAY, THURSDAY,
FRIDAY, SATURDAY, and SUNDAY are provided for
convenience. For example, to set the first weekday to Sunday:
import calendar
calendar.setfirstweekday(calendar.SUNDAY)
-
calendar.firstweekday()¶
Returns the current setting for the weekday to start each week.
-
calendar.isleap(year)¶
Returns True if year is a leap year, otherwise False.
-
calendar.leapdays(y1, y2)¶
Returns the number of leap years in the range from y1 to y2 (exclusive),
where y1 and y2 are years.
This function works for ranges spanning a century change.
-
calendar.weekday(year, month, day)¶
Returns the day of the week (0 is Monday) for year (1970–…),
month (1–12), day (1–31).
-
calendar.weekheader(width)¶
Return a header containing abbreviated weekday names. width specifies the width in
characters for one weekday.
-
calendar.monthrange(year, month)¶
Returns weekday of first day of the month and number of days in month, for the
specified year and month.
-
calendar.monthcalendar(year, month)¶
Returns a matrix representing a month’s calendar. Each row represents a week;
days outside of the month are represented by zeros. Each week begins with Monday
unless set by setfirstweekday().
-
calendar.prmonth(theyear, themonth, w=0, l=0)¶
Prints a month’s calendar as returned by month().
-
calendar.month(theyear, themonth, w=0, l=0)¶
Returns a month’s calendar in a multi-line string using the formatmonth()
of the TextCalendar class.
-
calendar.prcal(theyear, w=0, l=0, c=6, m=3)¶
Prints the calendar for an entire year as returned by
calendar().
-
calendar.calendar(theyear, w=2, l=1, c=6, m=3)¶
Returns a 3-column calendar for an entire year as a multi-line string using
the formatyear() of the TextCalendar class.
-
calendar.timegm(tuple)¶
An unrelated but handy function that takes a time tuple such as returned by
the gmtime() function in the time module, and returns the
corresponding Unix timestamp value, assuming an epoch of 1970, and the POSIX
encoding. In fact, time.gmtime() and timegm() are each other’s
inverse.
The calendar module exports the following data attributes:
-
calendar.day_name¶
A sequence that represents the days of the week in the current locale,
where Monday is day number 0.
>>> import calendar
>>> list(calendar.day_name)
['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
-
calendar.day_abbr¶
A sequence that represents the abbreviated days of the week in the current locale,
where Mon is day number 0.
>>> import calendar
>>> list(calendar.day_abbr)
['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
-
calendar.MONDAY¶
-
calendar.TUESDAY¶
-
calendar.WEDNESDAY¶
-
calendar.THURSDAY¶
-
calendar.FRIDAY¶
-
calendar.SATURDAY¶
-
calendar.SUNDAY¶
Aliases for the days of the week,
where MONDAY is 0 and SUNDAY is 6.
-
class calendar.Day¶
Enumeration defining days of the week as integer constants.
The members of this enumeration are exported to the module scope as
MONDAY through SUNDAY.
-
calendar.month_name¶
A sequence that represents the months of the year in the current locale. This
follows normal convention of January being month number 1, so it has a length of
13 and month_name[0] is the empty string.
>>> import calendar
>>> list(calendar.month_name)
['', 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']
Caution
In locales with alternative month names forms, the month_name sequence
may not be suitable when a month name stands by itself and not as part of a date.
For instance, in Greek and in many Slavic and Baltic languages, month_name
will produce the month in genitive case. Use standalone_month_name for a form
suitable for standalone use.
-
calendar.month_abbr¶
A sequence that represents the abbreviated months of the year in the current
locale. This follows normal convention of January being month number 1, so it
has a length of 13 and month_abbr[0] is the empty string.
>>> import calendar
>>> list(calendar.month_abbr)
['', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
Caution
In locales with alternative month names forms, the month_abbr sequence
may not be suitable when a month name stands by itself and not as part of a date.
Use standalone_month_abbr for a form suitable for standalone use.
-
calendar.standalone_month_name¶
A sequence that represents the months of the year in the current locale
in the standalone form if the locale provides one. Else it is equivalent
to month_name.
-
calendar.standalone_month_abbr¶
A sequence that represents the abbreviated months of the year in the current
locale in the standalone form if the locale provides one. Else it is
equivalent to month_abbr.
-
calendar.JANUARY¶
-
calendar.FEBRUARY¶
-
calendar.MARCH¶
-
calendar.APRIL¶
-
calendar.MAY¶
-
calendar.JUNE¶
-
calendar.JULY¶
-
calendar.AUGUST¶
-
calendar.SEPTEMBER¶
-
calendar.OCTOBER¶
-
calendar.NOVEMBER¶
-
calendar.DECEMBER¶
Aliases for the months of the year,
where JANUARY is 1 and DECEMBER is 12.
-
class calendar.Month¶
Enumeration defining months of the year as integer constants.
The members of this enumeration are exported to the module scope as
JANUARY through DECEMBER.
The calendar module defines the following exceptions:
-
exception calendar.IllegalMonthError(month)¶
A subclass of ValueError and IndexError,
raised when the given month number is outside of the range 1-12 (inclusive).
Changed in version 3.12: IllegalMonthError is now also a subclass of
ValueError. New code should avoid catching
IndexError.
-
month¶
The invalid month number.
-
exception calendar.IllegalWeekdayError(weekday)¶
A subclass of ValueError,
raised when the given weekday number is outside of the range 0-6 (inclusive).
-
weekday¶
The invalid weekday number.
See also
- Module
datetime Object-oriented interface to dates and times with similar functionality to the
time module.
- Module
time Low-level time related functions.
Command-line usage¶
The calendar module can be executed as a script from the command line
to interactively print a calendar.
python -m calendar [-h] [-L LOCALE] [-e ENCODING] [-t {text,html}]
[-w WIDTH] [-l LINES] [-s SPACING] [-m MONTHS] [-c CSS]
[-f FIRST_WEEKDAY] [year] [month]
For example, to print a calendar for the year 2000:
$ python -m calendar 2000
2000
January February March
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 1 2 3 4 5 6 1 2 3 4 5
3 4 5 6 7 8 9 7 8 9 10 11 12 13 6 7 8 9 10 11 12
10 11 12 13 14 15 16 14 15 16 17 18 19 20 13 14 15 16 17 18 19
17 18 19 20 21 22 23 21 22 23 24 25 26 27 20 21 22 23 24 25 26
24 25 26 27 28 29 30 28 29 27 28 29 30 31
31
April May June
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 1 2 3 4 5 6 7 1 2 3 4
3 4 5 6 7 8 9 8 9 10 11 12 13 14 5 6 7 8 9 10 11
10 11 12 13 14 15 16 15 16 17 18 19 20 21 12 13 14 15 16 17 18
17 18 19 20 21 22 23 22 23 24 25 26 27 28 19 20 21 22 23 24 25
24 25 26 27 28 29 30 29 30 31 26 27 28 29 30
July August September
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 1 2 3 4 5 6 1 2 3
3 4 5 6 7 8 9 7 8 9 10 11 12 13 4 5 6 7 8 9 10
10 11 12 13 14 15 16 14 15 16 17 18 19 20 11 12 13 14 15 16 17
17 18 19 20 21 22 23 21 22 23 24 25 26 27 18 19 20 21 22 23 24
24 25 26 27 28 29 30 28 29 30 31 25 26 27 28 29 30
31
October November December
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 1 2 3 4 5 1 2 3
2 3 4 5 6 7 8 6 7 8 9 10 11 12 4 5 6 7 8 9 10
9 10 11 12 13 14 15 13 14 15 16 17 18 19 11 12 13 14 15 16 17
16 17 18 19 20 21 22 20 21 22 23 24 25 26 18 19 20 21 22 23 24
23 24 25 26 27 28 29 27 28 29 30 25 26 27 28 29 30 31
30 31
The following options are accepted:
-
--help, -h¶
Show the help message and exit.
-
--locale LOCALE, -L LOCALE¶
The locale to use for month and weekday names.
Defaults to English.
-
--encoding ENCODING, -e ENCODING¶
The encoding to use for output.
--encoding is required if --locale is set.
-
--type {text,html}, -t {text,html}¶
Print the calendar to the terminal as text,
or as an HTML document.
-
--first-weekday FIRST_WEEKDAY, -f FIRST_WEEKDAY¶
The weekday to start each week.
Must be a number between 0 (Monday) and 6 (Sunday).
Defaults to 0.
-
year¶
The year to print the calendar for.
Defaults to the current year.
-
month¶
The month of the specified year to print the calendar for.
Must be a number between 1 and 12.
Defaults to printing a calendar for the full year.
Text-mode options:
-
--width WIDTH, -w WIDTH¶
The width of the date column in terminal columns.
The date is printed centred in the column.
Any value lower than 2 is ignored.
Defaults to 2.
-
--lines LINES, -l LINES¶
The number of lines for each week in terminal rows.
The date is printed top-aligned.
Any value lower than 1 is ignored.
Defaults to 1.
-
--spacing SPACING, -s SPACING¶
The space between months in columns.
Any value lower than 2 is ignored.
Defaults to 6.
-
--months MONTHS, -m MONTHS¶
The number of months printed per row.
Defaults to 3.
HTML-mode options:
-
--css CSS, -c CSS¶
The path of a CSS stylesheet to use for the calendar.
This must either be relative to the generated HTML,
or an absolute HTTP or file:/// URL.
© Copyright 2001 Python Software Foundation.
This page is licensed under the Python Software Foundation License Version 2.
Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
See History and License for more information.
The Python Software Foundation is a non-profit corporation.
Please donate.
Last updated on Nov 12, 2026 (08:53 UTC).
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