diff options
Diffstat (limited to 'Demo')
| -rw-r--r-- | Demo/classes/Dates.py | 97 |
1 files changed, 48 insertions, 49 deletions
diff --git a/Demo/classes/Dates.py b/Demo/classes/Dates.py index 857bc90..63488ce 100644 --- a/Demo/classes/Dates.py +++ b/Demo/classes/Dates.py @@ -1,43 +1,45 @@ -# Class Date supplies date objects that support date arithmetic. -# -# Date(month,day,year) returns a Date object. An instance prints as, -# e.g., 'Mon 16 Aug 1993'. -# -# Addition, subtraction, comparison operators, min, max, and sorting -# all work as expected for date objects: int+date or date+int returns -# the date `int' days from `date'; date+date raises an exception; -# date-int returns the date `int' days before `date'; date2-date1 returns -# an integer, the number of days from date1 to date2; int-date raises an -# exception; date1 < date2 is true iff date1 occurs before date2 (& -# similarly for other comparisons); min(date1,date2) is the earlier of -# the two dates and max(date1,date2) the later; and date objects can be -# used as dictionary keys. -# -# Date objects support one visible method, date.weekday(). This returns -# the day of the week the date falls on, as a string. -# -# Date objects also have 4 read-only data attributes: -# .month in 1..12 -# .day in 1..31 -# .year int or long int -# .ord the ordinal of the date relative to an arbitrary staring point -# -# The Dates module also supplies function today(), which returns the -# current date as a date object. -# -# Those entranced by calendar trivia will be disappointed, as no attempt -# has been made to accommodate the Julian (etc) system. On the other -# hand, at least this package knows that 2000 is a leap year but 2100 -# isn't, and works fine for years with a hundred decimal digits <wink>. - -# Tim Peters tim@ksr.com -# not speaking for Kendall Square Research Corp - -# Adapted to Python 1.1 (where some hacks to overcome coercion are unnecessary) -# by Guido van Rossum - -# Note that as of Python 2.3, a datetime module is included in the stardard -# library. +""" +Class Date supplies date objects that support date arithmetic. + +Date(month,day,year) returns a Date object. An instance prints as, +e.g., 'Mon 16 Aug 1993'. + +Addition, subtraction, comparison operators, min, max, and sorting +all work as expected for date objects: int+date or date+int returns +the date `int' days from `date'; date+date raises an exception; +date-int returns the date `int' days before `date'; date2-date1 returns +an integer, the number of days from date1 to date2; int-date raises an +exception; date1 < date2 is true iff date1 occurs before date2 (& +similarly for other comparisons); min(date1,date2) is the earlier of +the two dates and max(date1,date2) the later; and date objects can be +used as dictionary keys. + +Date objects support one visible method, date.weekday(). This returns +the day of the week the date falls on, as a string. + +Date objects also have 4 read-only data attributes: + .month in 1..12 + .day in 1..31 + .year int or long int + .ord the ordinal of the date relative to an arbitrary staring point + +The Dates module also supplies function today(), which returns the +current date as a date object. + +Those entranced by calendar trivia will be disappointed, as no attempt +has been made to accommodate the Julian (etc) system. On the other +hand, at least this package knows that 2000 is a leap year but 2100 +isn't, and works fine for years with a hundred decimal digits <wink>. + +Tim Peters tim@ksr.com +not speaking for Kendall Square Research Corp + +Adapted to Python 1.1 (where some hacks to overcome coercion are unnecessary) +by Guido van Rossum + +Note that as of Python 2.3, a datetime module is included in the stardard +library. +""" import functools @@ -86,8 +88,9 @@ def _num2date(n): # return date with ordinal n if not isinstance(n, int): raise TypeError('argument must be integer: %r' % type(n)) - ans = Date(1,1,1) # arguments irrelevant; just getting a Date obj - del ans.ord, ans.month, ans.day, ans.year # un-initialize it + # Get uninitialized Date object. This is necesary because once + # attributes are set, they cannot be changed. + ans = Date.__new__(Date) ans.ord = n n400 = (n-1)//_DI400Y # # of 400-year blocks preceding @@ -97,11 +100,7 @@ def _num2date(n): # return date with ordinal n if dby >= n: more = more - 1 dby = dby - _days_in_year(more) - year, n = year + more, int(n - dby) - - try: year = int(year) # chop to int, if it fits - except (ValueError, OverflowError): pass - + year, n = year + more, n - dby month = min(n//29 + 1, 12) dbm = _days_before_month(month, year) if dbm >= n: @@ -112,7 +111,7 @@ def _num2date(n): # return date with ordinal n return ans def _num2day(n): # return weekday name of day with ordinal n - return _DAY_NAMES[ int(n % 7) ] + return _DAY_NAMES[n % 7] @functools.total_ordering class Date: @@ -122,7 +121,7 @@ class Date: dim = _days_in_month(month, year) if not 1 <= day <= dim: raise ValueError('day must be in 1..%r: %r' % (dim, day)) - self.month, self.day, self.year = month, day, year + self.month, self.day, self.year = map(int, (month, day, year)) self.ord = _date2num(self) # don't allow setting existing attributes |