Setting values on non-existing datetime index raises exception only when index has DST changes in range #18308
Labels
good first issue
Testing
pandas testing functions or related to the test suite
Timezones
Timezone data dtype
Milestone
Setting values on datetime index with DST changes
Exception raised from `df.loc`
AmbiguousTimeError Traceback (most recent call last) in () ----> 1 df.loc[pd.Timestamp('2016-10-10 03:00:00', tz='Europe/Madrid'), 'value'] = 12~/Envs/jupyter/lib/python3.6/site-packages/pandas/core/indexing.py in setitem(self, key, value)
192 key = com._apply_if_callable(key, self.obj)
193 indexer = self._get_setitem_indexer(key)
--> 194 self._setitem_with_indexer(indexer, value)
195
196 def _has_valid_type(self, k, axis):
~/Envs/jupyter/lib/python3.6/site-packages/pandas/core/indexing.py in _setitem_with_indexer(self, indexer, value)
368 # so the object is the same
369 index = self.obj._get_axis(i)
--> 370 labels = index.insert(len(index), key)
371 self.obj._data = self.obj.reindex(labels, axis=i)._data
372 self.obj._maybe_update_cacher(clear=True)
~/Envs/jupyter/lib/python3.6/site-packages/pandas/core/indexes/datetimes.py in insert(self, loc, item)
1734 new_dates = libts.tz_convert(new_dates, 'UTC', self.tz)
1735 return DatetimeIndex(new_dates, name=self.name, freq=freq,
-> 1736 tz=self.tz)
1737
1738 except (AttributeError, TypeError):
~/Envs/jupyter/lib/python3.6/site-packages/pandas/util/_decorators.py in wrapper(*args, **kwargs)
116 else:
117 kwargs[new_arg_name] = new_arg_value
--> 118 return func(*args, **kwargs)
119 return wrapper
120 return _deprecate_kwarg
~/Envs/jupyter/lib/python3.6/site-packages/pandas/core/indexes/datetimes.py in new(cls, data, freq, start, end, periods, copy, name, tz, verify_integrity, normalize, closed, ambiguous, dtype, **kwargs)
388 ints = subarr.view('i8')
389 subarr = libts.tz_localize_to_utc(ints, tz,
--> 390 ambiguous=ambiguous)
391 subarr = subarr.view(_NS_DTYPE)
392
pandas/_libs/tslib.pyx in pandas._libs.tslib.tz_localize_to_utc()
AmbiguousTimeError: Cannot infer dst time from Timestamp('2017-10-29 02:00:00'), try using the 'ambiguous' argument
Setting values on datetime index with no DST changes
Problem description
There seems to be conflicting behaviors when setting values on non-existing index (a datetime that's not already in index) with
.loc
.(First code sample) When the datetime index range has DST changes
.loc[index, field] = value
raises an AmbiguousTimeError.(Second code sample) When the datetime index range does not have DST changes
.loc[index, field] = value
creates a new row as normalOutput of
pd.show_versions()
[paste the output of
pd.show_versions()
here below this line]INSTALLED VERSIONS
commit: None
python: 3.6.3.final.0
python-bits: 64
OS: Darwin
OS-release: 17.2.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: en_US.UTF-8
LANG: en_US.utf8
LOCALE: en_US.UTF-8
pandas: 0.21.0
pytest: None
pip: 9.0.1
setuptools: 36.7.2
Cython: None
numpy: 1.13.3
scipy: None
pyarrow: None
xarray: None
IPython: 6.2.1
sphinx: None
patsy: None
dateutil: 2.6.1
pytz: 2017.3
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: None
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: 1.0b10
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
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