process data related to date

datetime_safe.py

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+# Python's datetime strftime doesn't handle dates before 1900.
+# These classes override date and datetime to support the formatting of a date
+# through its full "proleptic Gregorian" date range.
+#
+# Based on code submitted to comp.lang.python by Andrew Dalke
+#
+# >>> datetime_safe.date(1850, 8, 2).strftime("%Y/%m/%d was a %A")
+# '1850/08/02 was a Friday'
+
+from datetime import date as real_date, time as real_time, datetime as real_datetime
+import re
+import time as ttime
+
+
+class date(real_date):
+    def strftime(self, fmt):
+        return strftime(self, fmt)
+
+
+class datetime(real_datetime):
+    def strftime(self, fmt):
+        return strftime(self, fmt)
+
+    @classmethod
+    def combine(cls, date, time):
+        return cls(date.year, date.month, date.day,
+                   time.hour, time.minute, time.second,
+                   time.microsecond, time.tzinfo)
+
+    def date(self):
+        return date(self.year, self.month, self.day)
+
+
+class time(real_time):
+    pass
+
+
+def new_date(d):
+    "Generate a safe date from a datetime.date object."
+    return date(d.year, d.month, d.day)
+
+
+def new_datetime(d):
+    """
+    Generate a safe datetime from a datetime.date or datetime.datetime object.
+    """
+    kw = [d.year, d.month, d.day]
+    if isinstance(d, real_datetime):
+        kw.extend([d.hour, d.minute, d.second, d.microsecond, d.tzinfo])
+    return datetime(*kw)
+
+# This library does not support strftime's "%s" or "%y" format strings.
+# Allowed if there's an even number of "%"s because they are escaped.
+_illegal_formatting = re.compile(r"((^|[^%])(%%)*%[sy])")
+
+
+def _findall(text, substr):
+    # Also finds overlaps
+    sites = []
+    i = 0
+    while 1:
+        j = text.find(substr, i)
+        if j == -1:
+            break
+        sites.append(j)
+        i = j + 1
+    return sites
+
+
+def strftime(dt, fmt):
+    if dt.year >= 1900:
+        return super(type(dt), dt).strftime(fmt)
+    illegal_formatting = _illegal_formatting.search(fmt)
+    if illegal_formatting:
+        raise TypeError("strftime of dates before 1900 does not handle" + illegal_formatting.group(0))
+
+    year = dt.year
+    # For every non-leap year century, advance by
+    # 6 years to get into the 28-year repeat cycle
+    delta = 2000 - year
+    off = 6 * (delta // 100 + delta // 400)
+    year = year + off
+
+    # Move to around the year 2000
+    year = year + ((2000 - year) // 28) * 28
+    timetuple = dt.timetuple()
+    s1 = ttime.strftime(fmt, (year,) + timetuple[1:])
+    sites1 = _findall(s1, str(year))
+
+    s2 = ttime.strftime(fmt, (year + 28,) + timetuple[1:])
+    sites2 = _findall(s2, str(year + 28))
+
+    sites = []
+    for site in sites1:
+        if site in sites2:
+            sites.append(site)
+
+    s = s1
+    syear = "%04d" % (dt.year,)
+    for site in sites:
+        s = s[:site] + syear + s[site + 4:]
+    return s

requirements.txt

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+dateutil==2.4.2
+six==1.2.0