calendar — General calendar-related functions

Source code: Lib/calendar.py

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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. 0 is Monday (the default), 6 is Sunday.

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:

iterweekdays()

Return an iterator for the week day 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 week day 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.

New in version 3.7.

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.

New in version 3.7.

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:

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.

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 the system default encoding).

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.

New in version 3.7.

cssclasses_weekday_head

A list of CSS classes used for weekday names in the header row. The default is the same as cssclasses.

New in version 3.7.

cssclass_month_head

The month’s head CSS class (used by formatmonthname()). The default value is "month".

New in version 3.7.

cssclass_month

The CSS class for the whole month’s table (used by formatmonth()). The default value is "month".

New in version 3.7.

cssclass_year

The CSS class for the whole year’s table of tables (used by formatyear()). The default value is "year".

New in version 3.7.

cssclass_year_head

The CSS class for the table head for the whole year (used by formatyear()). The default value is "year".

New in version 3.7.

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:

"text-bold text-red"

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. If this locale includes an encoding all strings containing month and weekday names will be returned as unicode.

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. If this locale includes an encoding all strings containing month and weekday names will be returned as unicode.

For simple text calendars this module provides the following functions.

calendar.setfirstweekday(weekday)

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(n)

Return a header containing abbreviated weekday names. n 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 a 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(year, w=0, l=0, c=6, m=3)

Prints the calendar for an entire year as returned by calendar().

calendar.calendar(year, 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 others’ inverse.

The calendar module exports the following data attributes:

calendar.day_name

An array that represents the days of the week in the current locale.

calendar.day_abbr

An array that represents the abbreviated days of the week in the current locale.

calendar.month_name

An array 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.

calendar.month_abbr

An array 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.