Mercurial > cpython-lru_cache-weakref
annotate Demo/classes/Dates.py @ 5817:48b94de85bf3 legacy-trunk
Extensive changes by AMK.
| author | Guido van Rossum <guido@python.org> |
|---|---|
| date | Thu, 17 Jul 1997 16:29:42 +0000 |
| parents | dd7be8128410 |
| children | 4278561bd5e8 |
| rev | line source |
|---|---|
| 1378 | 1 # Class Date supplies date objects that support date arithmetic. |
| 2 # | |
| 3 # Date(month,day,year) returns a Date object. An instance prints as, | |
| 4 # e.g., 'Mon 16 Aug 1993'. | |
| 5 # | |
| 6 # Addition, subtraction, comparison operators, min, max, and sorting | |
| 7 # all work as expected for date objects: int+date or date+int returns | |
| 8 # the date `int' days from `date'; date+date raises an exception; | |
| 9 # date-int returns the date `int' days before `date'; date2-date1 returns | |
| 10 # an integer, the number of days from date1 to date2; int-date raises an | |
| 11 # exception; date1 < date2 is true iff date1 occurs before date2 (& | |
| 12 # similarly for other comparisons); min(date1,date2) is the earlier of | |
| 13 # the two dates and max(date1,date2) the later; and date objects can be | |
| 14 # used as dictionary keys. | |
| 15 # | |
| 16 # Date objects support one visible method, date.weekday(). This returns | |
| 17 # the day of the week the date falls on, as a string. | |
| 18 # | |
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19 # Date objects also have 4 read-only data attributes: |
| 1378 | 20 # .month in 1..12 |
| 21 # .day in 1..31 | |
| 22 # .year int or long int | |
| 23 # .ord the ordinal of the date relative to an arbitrary staring point | |
| 24 # | |
| 25 # The Dates module also supplies function today(), which returns the | |
| 26 # current date as a date object. | |
| 27 # | |
| 28 # Those entranced by calendar trivia will be disappointed, as no attempt | |
| 29 # has been made to accommodate the Julian (etc) system. On the other | |
| 30 # hand, at least this package knows that 2000 is a leap year but 2100 | |
| 31 # isn't, and works fine for years with a hundred decimal digits <wink>. | |
| 32 | |
| 33 # Tim Peters tim@ksr.com | |
| 34 # not speaking for Kendall Square Research Corp | |
| 35 | |
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36 # Adapted to Python 1.1 (where some hacks to overcome coercion are unnecessary) |
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37 # by Guido van Rossum |
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38 |
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39 # vi:set tabsize=8: |
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40 |
| 1378 | 41 _MONTH_NAMES = [ 'January', 'February', 'March', 'April', 'May', |
| 42 'June', 'July', 'August', 'September', 'October', | |
| 43 'November', 'December' ] | |
| 44 | |
| 45 _DAY_NAMES = [ 'Friday', 'Saturday', 'Sunday', 'Monday', | |
| 46 'Tuesday', 'Wednesday', 'Thursday' ] | |
| 47 | |
| 48 _DAYS_IN_MONTH = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ] | |
| 49 | |
| 50 _DAYS_BEFORE_MONTH = [] | |
| 51 dbm = 0 | |
| 52 for dim in _DAYS_IN_MONTH: | |
| 53 _DAYS_BEFORE_MONTH.append(dbm) | |
| 54 dbm = dbm + dim | |
| 55 del dbm, dim | |
| 56 | |
| 57 _INT_TYPES = type(1), type(1L) | |
| 58 | |
| 59 def _is_leap( year ): # 1 if leap year, else 0 | |
| 60 if year % 4 != 0: return 0 | |
| 61 if year % 400 == 0: return 1 | |
| 62 return year % 100 != 0 | |
| 63 | |
| 64 def _days_in_year( year ): # number of days in year | |
| 65 return 365 + _is_leap(year) | |
| 66 | |
| 67 def _days_before_year( year ): # number of days before year | |
| 68 return year*365L + (year+3)/4 - (year+99)/100 + (year+399)/400 | |
| 69 | |
| 70 def _days_in_month( month, year ): # number of days in month of year | |
| 71 if month == 2 and _is_leap(year): return 29 | |
| 72 return _DAYS_IN_MONTH[month-1] | |
| 73 | |
| 74 def _days_before_month( month, year ): # number of days in year before month | |
| 75 return _DAYS_BEFORE_MONTH[month-1] + (month > 2 and _is_leap(year)) | |
| 76 | |
| 77 def _date2num( date ): # compute ordinal of date.month,day,year | |
| 78 return _days_before_year( date.year ) + \ | |
| 79 _days_before_month( date.month, date.year ) + \ | |
| 80 date.day | |
| 81 | |
| 82 _DI400Y = _days_before_year( 400 ) # number of days in 400 years | |
| 83 | |
| 84 def _num2date( n ): # return date with ordinal n | |
| 85 if type(n) not in _INT_TYPES: | |
| 86 raise TypeError, 'argument must be integer: ' + `type(n)` | |
| 87 | |
| 88 ans = Date(1,1,1) # arguments irrelevant; just getting a Date obj | |
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89 del ans.ord, ans.month, ans.day, ans.year # un-initialize it |
| 1378 | 90 ans.ord = n |
| 91 | |
| 92 n400 = (n-1)/_DI400Y # # of 400-year blocks preceding | |
| 93 year, n = 400 * n400, n - _DI400Y * n400 | |
| 94 more = n / 365 | |
| 95 dby = _days_before_year( more ) | |
| 96 if dby >= n: | |
| 97 more = more - 1 | |
| 98 dby = dby - _days_in_year( more ) | |
| 99 year, n = year + more, int(n - dby) | |
| 100 | |
| 101 try: year = int(year) # chop to int, if it fits | |
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102 except (ValueError, OverflowError): pass |
| 1378 | 103 |
| 104 month = min( n/29 + 1, 12 ) | |
| 105 dbm = _days_before_month( month, year ) | |
| 106 if dbm >= n: | |
| 107 month = month - 1 | |
| 108 dbm = dbm - _days_in_month( month, year ) | |
| 109 | |
| 110 ans.month, ans.day, ans.year = month, n-dbm, year | |
| 111 return ans | |
| 112 | |
| 113 def _num2day( n ): # return weekday name of day with ordinal n | |
| 114 return _DAY_NAMES[ int(n % 7) ] | |
| 115 | |
| 116 | |
| 117 class Date: | |
| 118 def __init__( self, month, day, year ): | |
| 119 if not 1 <= month <= 12: | |
| 120 raise ValueError, 'month must be in 1..12: ' + `month` | |
| 121 dim = _days_in_month( month, year ) | |
| 122 if not 1 <= day <= dim: | |
| 123 raise ValueError, 'day must be in 1..' + `dim` + ': ' + `day` | |
| 124 self.month, self.day, self.year = month, day, year | |
| 125 self.ord = _date2num( self ) | |
| 126 | |
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127 # don't allow setting existing attributes |
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128 def __setattr__( self, name, value ): |
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129 if self.__dict__.has_key(name): |
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130 raise AttributeError, 'read-only attribute ' + name |
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131 self.__dict__[name] = value |
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132 |
| 1378 | 133 def __cmp__( self, other ): |
| 134 return cmp( self.ord, other.ord ) | |
| 135 | |
| 136 # define a hash function so dates can be used as dictionary keys | |
| 137 def __hash__( self ): | |
| 138 return hash( self.ord ) | |
| 139 | |
| 140 # print as, e.g., Mon 16 Aug 1993 | |
| 141 def __repr__( self ): | |
| 142 return '%.3s %2d %.3s ' % ( | |
| 143 self.weekday(), | |
| 144 self.day, | |
| 145 _MONTH_NAMES[self.month-1] ) + `self.year` | |
| 146 | |
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147 # Python 1.1 coerces neither int+date nor date+int |
| 1378 | 148 def __add__( self, n ): |
| 149 if type(n) not in _INT_TYPES: | |
| 150 raise TypeError, 'can\'t add ' + `type(n)` + ' to date' | |
| 151 return _num2date( self.ord + n ) | |
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152 __radd__ = __add__ # handle int+date |
| 1378 | 153 |
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154 # Python 1.1 coerces neither date-int nor date-date |
| 1378 | 155 def __sub__( self, other ): |
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156 if type(other) in _INT_TYPES: # date-int |
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157 return _num2date( self.ord - other ) |
| 1378 | 158 else: |
| 159 return self.ord - other.ord # date-date | |
| 160 | |
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161 # complain about int-date |
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162 def __rsub__( self, other ): |
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163 raise TypeError, 'Can\'t subtract date from integer' |
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164 |
| 1378 | 165 def weekday( self ): |
| 166 return _num2day( self.ord ) | |
| 167 | |
| 168 def today(): | |
| 169 import time | |
| 170 local = time.localtime(time.time()) | |
| 171 return Date( local[1], local[2], local[0] ) | |
| 172 | |
| 173 DateTestError = 'DateTestError' | |
| 174 def test( firstyear, lastyear ): | |
| 175 a = Date(9,30,1913) | |
| 176 b = Date(9,30,1914) | |
| 177 if `a` != 'Tue 30 Sep 1913': | |
| 178 raise DateTestError, '__repr__ failure' | |
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179 if (not a < b) or a == b or a > b or b != b: |
| 1378 | 180 raise DateTestError, '__cmp__ failure' |
| 181 if a+365 != b or 365+a != b: | |
| 182 raise DateTestError, '__add__ failure' | |
| 183 if b-a != 365 or b-365 != a: | |
| 184 raise DateTestError, '__sub__ failure' | |
| 185 try: | |
| 186 x = 1 - a | |
| 187 raise DateTestError, 'int-date should have failed' | |
| 188 except TypeError: | |
| 189 pass | |
| 190 try: | |
| 191 x = a + b | |
| 192 raise DateTestError, 'date+date should have failed' | |
| 193 except TypeError: | |
| 194 pass | |
| 195 if a.weekday() != 'Tuesday': | |
| 196 raise DateTestError, 'weekday() failure' | |
| 197 if max(a,b) is not b or min(a,b) is not a: | |
| 198 raise DateTestError, 'min/max failure' | |
| 199 d = {a-1:b, b:a+1} | |
| 200 if d[b-366] != b or d[a+(b-a)] != Date(10,1,1913): | |
| 201 raise DateTestError, 'dictionary failure' | |
| 202 | |
| 203 # verify date<->number conversions for first and last days for | |
| 204 # all years in firstyear .. lastyear | |
| 205 | |
| 206 lord = _days_before_year( firstyear ) | |
| 207 y = firstyear | |
| 208 while y <= lastyear: | |
| 209 ford = lord + 1 | |
| 210 lord = ford + _days_in_year(y) - 1 | |
| 211 fd, ld = Date(1,1,y), Date(12,31,y) | |
| 212 if (fd.ord,ld.ord) != (ford,lord): | |
| 213 raise DateTestError, ('date->num failed', y) | |
| 214 fd, ld = _num2date(ford), _num2date(lord) | |
| 215 if (1,1,y,12,31,y) != \ | |
| 216 (fd.month,fd.day,fd.year,ld.month,ld.day,ld.year): | |
| 217 raise DateTestError, ('num->date failed', y) | |
| 218 y = y + 1 |