ENH: Parse %z directive in format for to_datetime

return timedeltas as list

return timedeltas in a numpy array

some flake fixes

Author: mroeschke

pandas/_libs/tslibs/strptime.pyx

@@ -29,7 +29,8 @@ cimport cython
 import numpy as np
 from numpy cimport ndarray, int64_t
 
-from datetime import date as datetime_date
+from datetime import (date as datetime_date, timedelta as datetime_timedelta,
+                      timezone as datetime_timezone)
 from cpython.datetime cimport datetime
 
 from np_datetime cimport (check_dts_bounds,
@@ -58,6 +59,7 @@ def array_strptime(ndarray[object] values, object fmt,
         Py_ssize_t i, n = len(values)
         pandas_datetimestruct dts
         ndarray[int64_t] iresult
+        ndarray[object] results_tz
         int year, month, day, minute, hour, second, weekday, julian, tz
         int week_of_year, week_of_year_start
         int64_t us, ns
@@ -109,6 +111,8 @@ def array_strptime(ndarray[object] values, object fmt,
     result = np.empty(n, dtype='M8[ns]')
     iresult = result.view('i8')
 
+    results_tz = np.empty(n, dtype='object')
+
     dts.us = dts.ps = dts.as = 0
 
     cdef dict _parse_code_table = {
@@ -130,7 +134,8 @@ def array_strptime(ndarray[object] values, object fmt,
         'U': 15,
         'W': 16,
         'Z': 17,
-        'p': 18   # just an additional key, works only with I
+        'p': 18,  # just an additional key, works only with I
+        'z': 19,
     }
     cdef int parse_code
 
@@ -177,6 +182,8 @@ def array_strptime(ndarray[object] values, object fmt,
         month = day = 1
         hour = minute = second = ns = us = 0
         tz = -1
+        gmtoff = None
+        gmtoff_fraction = 0
         # Default to -1 to signify that values not known; not critical to have,
         # though
         week_of_year = -1
@@ -281,6 +288,32 @@ def array_strptime(ndarray[object] values, object fmt,
                         else:
                             tz = value
                             break
+            elif parse_code == 19:
+                z = found_dict['z']
+                if z == 'Z':
+                    gmtoff = 0
+                else:
+                    if z[3] == ':':
+                        z = z[:3] + z[4:]
+                        if len(z) > 5:
+                            if z[5] != ':':
+                                msg = "Unconsistent use of : in {0}"
+                                raise ValueError(msg.format(found_dict['z']))
+                            z = z[:5] + z[6:]
+                    hours = int(z[1:3])
+                    minutes = int(z[3:5])
+                    seconds = int(z[5:7] or 0)
+                    gmtoff = (hours * 60 * 60) + (minutes * 60) + seconds
+                    gmtoff_remainder = z[8:]
+                    # Pad to always return microseconds.
+                    pad_number = 6 - len(gmtoff_remainder)
+                    gmtoff_remainder_padding = "0" * pad_number
+                    gmtoff_fraction = int(gmtoff_remainder +
+                                          gmtoff_remainder_padding)
+                    if z.startswith("-"):
+                        gmtoff = -gmtoff
+                        gmtoff_fraction = -gmtoff_fraction
+
         # If we know the wk of the year and what day of that wk, we can figure
         # out the Julian day of the year.
         if julian == -1 and week_of_year != -1 and weekday != -1:
@@ -330,7 +363,17 @@ def array_strptime(ndarray[object] values, object fmt,
                 continue
             raise
 
-    return result
+        if gmtoff is not None:
+            tzdelta = datetime_timedelta(seconds=gmtoff,
+                                         microseconds=gmtoff_fraction)
+            tzname = found_dict.get('Z')
+            if tzname:
+                tzinfo = datetime_timezone(tzdelta, tzname)
+            else:
+                tzinfo = datetime_timezone(tzdelta, tzname)
+            results_tz[i] = tzinfo
+
+    return result, results_tz
 
 
 """_getlang, LocaleTime, TimeRE, _calc_julian_from_U_or_W are vendored
@@ -538,6 +581,7 @@ class TimeRE(dict):
             # XXX: Does 'Y' need to worry about having less or more than
             #     4 digits?
             'Y': r"(?P<Y>\d\d\d\d)",
+            'z': r"(?P<z>[+-]\d\d:?[0-5]\d(:?[0-5]\d(\.\d{1,6})?)?|Z)",
             'A': self.__seqToRE(self.locale_time.f_weekday, 'A'),
             'a': self.__seqToRE(self.locale_time.a_weekday, 'a'),
             'B': self.__seqToRE(self.locale_time.f_month[1:], 'B'),

pandas/core/tools/datetimes.py

@@ -344,7 +344,7 @@ def _convert_listlike(arg, box, format, name=None, tz=tz):
                 if result is None:
                     try:
                         result = array_strptime(arg, format, exact=exact,
-                                                errors=errors)
+                                                errors=errors)[0]
                     except tslib.OutOfBoundsDatetime:
                         if errors == 'raise':
                             raise