This is a minor bug-fix release in the 0.19.x series and includes some small regression fixes, bug fixes and performance improvements. We recommend that all users upgrade to this version.
Highlights include:
Compatibility with Python 3.6
Added a Pandas Cheat Sheet. (GH13202).
What’s new in v0.19.2
Enhancements
Performance improvements
Bug fixes
Contributors
The pd.merge_asof(), added in 0.19.0, gained some improvements:
pd.merge_asof()
pd.merge_asof() gained left_index/right_index and left_by/right_by arguments (GH14253)
left_index
right_index
left_by
right_by
pd.merge_asof() can take multiple columns in by parameter and has specialized dtypes for better performance (GH13936)
by
Performance regression with PeriodIndex (GH14822)
PeriodIndex
Performance regression in indexing with getitem (GH14930)
Improved performance of .replace() (GH12745)
.replace()
Improved performance Series creation with a datetime index and dictionary data (GH14894)
Series
Compat with python 3.6 for pickling of some offsets (GH14685)
Compat with python 3.6 for some indexing exception types (GH14684, GH14689)
Compat with python 3.6 for deprecation warnings in the test suite (GH14681)
Compat with python 3.6 for Timestamp pickles (GH14689)
Compat with dateutil==2.6.0; segfault reported in the testing suite (GH14621)
dateutil==2.6.0
Allow nanoseconds in Timestamp.replace as a kwarg (GH14621)
nanoseconds
Timestamp.replace
Bug in pd.read_csv in which aliasing was being done for na_values when passed in as a dictionary (GH14203)
pd.read_csv
na_values
Bug in pd.read_csv in which column indices for a dict-like na_values were not being respected (GH14203)
Bug in pd.read_csv where reading files fails, if the number of headers is equal to the number of lines in the file (GH14515)
Bug in pd.read_csv for the Python engine in which an unhelpful error message was being raised when multi-char delimiters were not being respected with quotes (GH14582)
Fix bugs (GH14734, GH13654) in pd.read_sas and pandas.io.sas.sas7bdat.SAS7BDATReader that caused problems when reading a SAS file incrementally.
pd.read_sas
pandas.io.sas.sas7bdat.SAS7BDATReader
Bug in pd.read_csv for the Python engine in which an unhelpful error message was being raised when skipfooter was not being respected by Python’s CSV library (GH13879)
skipfooter
Bug in .fillna() in which timezone aware datetime64 values were incorrectly rounded (GH14872)
.fillna()
Bug in .groupby(..., sort=True) of a non-lexsorted MultiIndex when grouping with multiple levels (GH14776)
.groupby(..., sort=True)
Bug in pd.cut with negative values and a single bin (GH14652)
pd.cut
Bug in pd.to_numeric where a 0 was not unsigned on a downcast='unsigned' argument (GH14401)
pd.to_numeric
downcast='unsigned'
Bug in plotting regular and irregular timeseries using shared axes (sharex=True or ax.twinx()) (GH13341, GH14322).
sharex=True
ax.twinx()
Bug in not propagating exceptions in parsing invalid datetimes, noted in python 3.6 (GH14561)
Bug in resampling a DatetimeIndex in local TZ, covering a DST change, which would raise AmbiguousTimeError (GH14682)
DatetimeIndex
AmbiguousTimeError
Bug in indexing that transformed RecursionError into KeyError or IndexingError (GH14554)
RecursionError
KeyError
IndexingError
Bug in HDFStore when writing a MultiIndex when using data_columns=True (GH14435)
HDFStore
MultiIndex
data_columns=True
Bug in HDFStore.append() when writing a Series and passing a min_itemsize argument containing a value for the index (GH11412)
HDFStore.append()
min_itemsize
index
Bug when writing to a HDFStore in table format with a min_itemsize value for the index and without asking to append (GH10381)
table
Bug in Series.groupby.nunique() raising an IndexError for an empty Series (GH12553)
Series.groupby.nunique()
IndexError
Bug in DataFrame.nlargest and DataFrame.nsmallest when the index had duplicate values (GH13412)
DataFrame.nlargest
DataFrame.nsmallest
Bug in clipboard functions on linux with python2 with unicode and separators (GH13747)
Bug in clipboard functions on Windows 10 and python 3 (GH14362, GH12807)
Bug in .to_clipboard() and Excel compat (GH12529)
.to_clipboard()
Bug in DataFrame.combine_first() for integer columns (GH14687).
DataFrame.combine_first()
Bug in pd.read_csv() in which the dtype parameter was not being respected for empty data (GH14712)
pd.read_csv()
dtype
Bug in pd.read_csv() in which the nrows parameter was not being respected for large input when using the C engine for parsing (GH7626)
nrows
Bug in pd.merge_asof() could not handle timezone-aware DatetimeIndex when a tolerance was specified (GH14844)
Explicit check in to_stata and StataWriter for out-of-range values when writing doubles (GH14618)
to_stata
StataWriter
Bug in .plot(kind='kde') which did not drop missing values to generate the KDE Plot, instead generating an empty plot. (GH14821)
.plot(kind='kde')
Bug in unstack() if called with a list of column(s) as an argument, regardless of the dtypes of all columns, they get coerced to object (GH11847)
unstack()
object
A total of 33 people contributed patches to this release. People with a “+” by their names contributed a patch for the first time.
Ajay Saxena +
Ben Kandel
Chris
Chris Ham +
Christopher C. Aycock
Daniel Himmelstein +
Dave Willmer +
Dr-Irv
Jeff Carey +
Jeff Reback
Joe Jevnik
Joris Van den Bossche
Julian Santander +
Kerby Shedden
Keshav Ramaswamy
Kevin Sheppard
Luca Scarabello +
Matt Roeschke +
Matti Picus +
Maximilian Roos
Mykola Golubyev +
Nate Yoder +
Nicholas Ver Halen +
Pawel Kordek
Pietro Battiston
Rodolfo Fernandez +
Tara Adiseshan +
Tom Augspurger
Yaroslav Halchenko
gfyoung
hesham.shabana@hotmail.com +
sinhrks
wandersoncferreira +