# 5.12 `calendar` -- General calendar-related functions

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.

`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)

`firstweekday`()
  Returns the current setting for the weekday to start each week.

`isleap`(year)
  Returns true if year is a leap year.

`leapdays`(y1, y2)
  Returns the number of leap years in the range [y1...y2).

`weekday`(year, month, day)
  Returns the day of the week (`0` is Monday) for year (`1970`-...), month (`1`-`12`), day (`1`-`31`).

`monthrange`(year, month)
  Returns weekday of first day of the month and number of days in month, for the specified year and month.

`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()`.

`prmonth`(theyear, themonth[, w[, l]])
  Prints a month's calendar as returned by `month()`.

`month`(theyear, themonth[, w[, l]])
  Returns 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 set by `setfirstweekday()`.

`prcal`(year[, w[, l[c]]])
  Prints the calendar for an entire year as returned by `calendar()`.

`calendar`(year[, w[, l[c]]])
  Returns a 3-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 set by `setfirstweekday()`.

`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.

See Also:

Module `time`:
  Low-level time related functions.