Doc/lib/libcalendar.tex

   1 \section{\module{calendar} ---
   2          General calendar-related functions}
   3
   4 \declaremodule{standard}{calendar}
   5 \modulesynopsis{Functions for working with calendars,
   6                 including some emulation of the \UNIX\ \program{cal}
   7                 program.}
   8 \sectionauthor{Drew Csillag}{drew_csillag@geocities.com}
   9
  10 This module allows you to output calendars like the \UNIX{}
  11 \program{cal} program, and provides additional useful functions
  12 related to the calendar. By default, these calendars have Monday as
  13 the first day of the week, and Sunday as the last (the European
  14 convention). Use \function{setfirstweekday()} to set the first day of the
  15 week to Sunday (6) or to any other weekday.  Parameters that specify
  16 dates are given as integers.
  17
  18 Most of these functions rely on the \module{datetime} module which
  19 uses an idealized calendar, the current Gregorian calendar indefinitely
  20 extended in both directions.  This matches the definition of the
  21 "proleptic Gregorian" calendar in Dershowitz and Reingold's book
  22 "Calendrical Calculations", where it's the base calendar for all
  23 computations.
  24
  25 \begin{funcdesc}{setfirstweekday}{weekday}
  26 Sets the weekday (\code{0} is Monday, \code{6} is Sunday) to start
  27 each week. The values \constant{MONDAY}, \constant{TUESDAY},
  28 \constant{WEDNESDAY}, \constant{THURSDAY}, \constant{FRIDAY},
  29 \constant{SATURDAY}, and \constant{SUNDAY} are provided for
  30 convenience. For example, to set the first weekday to Sunday:
  31
  32 \begin{verbatim}
  33 import calendar
  34 calendar.setfirstweekday(calendar.SUNDAY)
  35 \end{verbatim}
  36 \versionadded{2.0}
  37 \end{funcdesc}
  38
  39 \begin{funcdesc}{firstweekday}{}
  40 Returns the current setting for the weekday to start each week.
  41 \versionadded{2.0}
  42 \end{funcdesc}
  43
  44 \begin{funcdesc}{isleap}{year}
  45 Returns \constant{True} if \var{year} is a leap year, otherwise
  46 \constant{False}.
  47 \end{funcdesc}
  48
  49 \begin{funcdesc}{leapdays}{y1, y2}
  50 Returns the number of leap years in the range
  51 [\var{y1}\ldots\var{y2}), where \var{y1} and \var{y2} are years.
  52 \versionchanged[This function didn't work for ranges spanning
  53                 a century change in Python 1.5.2]{2.0}
  54 \end{funcdesc}
  55
  56 \begin{funcdesc}{weekday}{year, month, day}
  57 Returns the day of the week (\code{0} is Monday) for \var{year}
  58 (\code{1970}--\ldots), \var{month} (\code{1}--\code{12}), \var{day}
  59 (\code{1}--\code{31}).
  60 \end{funcdesc}
  61
  62 \begin{funcdesc}{weekheader}{n}
  63 Return a header containing abbreviated weekday names. \var{n} specifies
  64 the width in characters for one weekday.
  65 \end{funcdesc}
  66
  67 \begin{funcdesc}{monthrange}{year, month}
  68 Returns weekday of first day of the month and number of days in month,
  69 for the specified \var{year} and \var{month}.
  70 \end{funcdesc}
  71
  72 \begin{funcdesc}{monthcalendar}{year, month}
  73 Returns a matrix representing a month's calendar.  Each row represents
  74 a week; days outside of the month a represented by zeros.
  75 Each week begins with Monday unless set by \function{setfirstweekday()}.
  76 \end{funcdesc}
  77
  78 \begin{funcdesc}{prmonth}{theyear, themonth\optional{, w\optional{, l}}}
  79 Prints a month's calendar as returned by \function{month()}.
  80 \end{funcdesc}
  81
  82 \begin{funcdesc}{month}{theyear, themonth\optional{, w\optional{, l}}}
  83 Returns a month's calendar in a multi-line string. If \var{w} is
  84 provided, it specifies the width of the date columns, which are
  85 centered. If \var{l} is given, it specifies the number of lines that
  86 each week will use. Depends on the first weekday as set by
  87 \function{setfirstweekday()}.
  88 \versionadded{2.0}
  89 \end{funcdesc}
  90
  91 \begin{funcdesc}{prcal}{year\optional{, w\optional{, l\optional{c}}}}
  92 Prints the calendar for an entire year as returned by
  93 \function{calendar()}.
  94 \end{funcdesc}
  95
  96 \begin{funcdesc}{calendar}{year\optional{, w\optional{, l\optional{c}}}}
  97 Returns a 3-column calendar for an entire year as a multi-line string.
  98 Optional parameters \var{w}, \var{l}, and \var{c} are for date column
  99 width, lines per week, and number of spaces between month columns,
 100 respectively. Depends on the first weekday as set by
 101 \function{setfirstweekday()}.  The earliest year for which a calendar can
 102 be generated is platform-dependent.
 103 \versionadded{2.0}
 104 \end{funcdesc}
 105
 106 \begin{funcdesc}{timegm}{tuple}
 107 An unrelated but handy function that takes a time tuple such as
 108 returned by the \function{gmtime()} function in the \refmodule{time}
 109 module, and returns the corresponding \UNIX{} timestamp value, assuming
 110 an epoch of 1970, and the POSIX encoding.  In fact,
 111 \function{time.gmtime()} and \function{timegm()} are each others' inverse.
 112 \versionadded{2.0}
 113 \end{funcdesc}
 114
 115 The \module{calendar} module exports the following data attributes:
 116
 117 \begin{datadesc}{day_name}
 118 An array that represents the days of the week in the
 119 current locale.
 120 \end{datadesc}
 121
 122 \begin{datadesc}{day_abbr}
 123 An array that represents the abbreviated days of the week
 124 in the current locale.
 125 \end{datadesc}
 126
 127 \begin{datadesc}{month_name}
 128 An array that represents the months of the year in the
 129 current locale.  This follows normal convention
 130 of January being month number 1, so it has a length of 13 and
 131 \code{month_name[0]} is the empty string.
 132 \end{datadesc}
 133
 134 \begin{datadesc}{month_abbr}
 135 An array that represents the abbreviated months of the year
 136 in the current locale.  This follows normal convention
 137 of January being month number 1, so it has a length of 13 and
 138 \code{month_abbr[0]} is the empty string.
 139 \end{datadesc}
 140
 141 \begin{seealso}
 142   \seemodule{datetime}{Object-oriented interface to dates and times
 143                        with similar functionality to the
 144                        \refmodule{time} module.}
 145   \seemodule{time}{Low-level time related functions.}
 146 \end{seealso}