This is a minor bug-fix release from 0.19.0 and includes some small regression fixes,
bug fixes and performance improvements.
We recommend that all users upgrade to this version.
What’s new in v0.19.1
Fixed performance regression in factorization of Period data (GH14338)
Fixed performance regression in Series.asof(where) when where is a scalar (GH14461)
Improved performance in DataFrame.asof(where) when where is a scalar (GH14461)
Improved performance in .to_json() when lines=True (GH14408)
Improved performance in certain types of loc indexing with a MultiIndex (GH14551).
Source installs from PyPI will now again work without cython installed, as in previous versions (GH14204)
Compat with Cython 0.25 for building (GH14496)
Fixed regression where user-provided file handles were closed in read_csv (c engine) (GH14418).
Fixed regression in DataFrame.quantile when missing values where present in some columns (GH14357).
Fixed regression in Index.difference where the freq of a DatetimeIndex was incorrectly set (GH14323)
Added back pandas.core.common.array_equivalent with a deprecation warning (GH14555).
Bug in pd.read_csv for the C engine in which quotation marks were improperly parsed in skipped rows (GH14459)
Bug in pd.read_csv for Python 2.x in which Unicode quote characters were no longer being respected (GH14477)
Fixed regression in Index.append when categorical indices were appended (GH14545).
Fixed regression in pd.DataFrame where constructor fails when given dict with None value (GH14381)
Fixed regression in DatetimeIndex._maybe_cast_slice_bound when index is empty (GH14354).
Bug in localizing an ambiguous timezone when a boolean is passed (GH14402)
Bug in TimedeltaIndex addition with a Datetime-like object where addition overflow in the negative direction was not being caught (GH14068, GH14453)
Bug in string indexing against data with object Index may raise AttributeError (GH14424)
Correctly raise ValueError on empty input to pd.eval() and df.query() (GH13139)
Bug in RangeIndex.intersection when result is a empty set (GH14364).
Bug in groupby-transform broadcasting that could cause incorrect dtype coercion (GH14457)
Bug in Series.__setitem__ which allowed mutating read-only arrays (GH14359).
Bug in DataFrame.insert where multiple calls with duplicate columns can fail (GH14291)
pd.merge() will raise ValueError with non-boolean parameters in passed boolean type arguments (GH14434)
Bug in Timestamp where dates very near the minimum (1677-09) could underflow on creation (GH14415)
Bug in pd.concat where names of the keys were not propagated to the resulting MultiIndex (GH14252)
Bug in pd.concat where axis cannot take string parameters 'rows' or 'columns' (GH14369)
Bug in pd.concat with dataframes heterogeneous in length and tuple keys (GH14438)
Bug in MultiIndex.set_levels where illegal level values were still set after raising an error (GH13754)
Bug in DataFrame.to_json where lines=True and a value contained a } character (GH14391)
Bug in df.groupby causing an AttributeError when grouping a single index frame by a column and the index level (GH14327)
Bug in df.groupby where TypeError raised when pd.Grouper(key=...) is passed in a list (GH14334)
Bug in pd.pivot_table may raise TypeError or ValueError when index or columns
is not scalar and values is not specified (GH14380)
A total of 30 people contributed patches to this release. People with a
“+” by their names contributed a patch for the first time.
Adam Chainz +
Arash Rouhani +
Brandon M. Burroughs +
David Krych +
Iván Vallés Pérez +
Jon M. Mease +
Jon Mease +
Joris Van den Bossche
Josh Owen +
Keshav Ramaswamy +
Larry Ren +
Michael Felt +
Piotr Chromiec +
Robert Bradshaw +
Thiago Serafim +