# What’s new in 1.0.2 (March 12, 2020)#

These are the changes in pandas 1.0.2. See Release notes for a full changelog including other versions of pandas.

## Fixed regressions#

**Groupby**

Fixed regression in

`DataFrameGroupBy.agg()`

and`SeriesGroupBy.agg()`

which were failing on frames with`MultiIndex`

columns and a custom function (GH 31777)Fixed regression in

`groupby(..).rolling(..).apply()`

(`RollingGroupby`

) where the`raw`

parameter was ignored (GH 31754)Fixed regression in

`rolling(..).corr()`

when using a time offset (GH 31789)Fixed regression in

`groupby(..).nunique()`

which was modifying the original values if`NaN`

values were present (GH 31950)Fixed regression in

`DataFrame.groupby`

raising a`ValueError`

from an internal operation (GH 31802)Fixed regression in

`DataFrameGroupBy.agg()`

and`SeriesGroupBy.agg()`

calling a user-provided function an extra time on an empty input (GH 31760)

**I/O**

Fixed regression in

`read_csv()`

in which the`encoding`

option was not recognized with certain file-like objects (GH 31819)Fixed regression in

`DataFrame.to_excel()`

when the`columns`

keyword argument is passed (GH 31677)Fixed regression in

`ExcelFile`

where the stream passed into the function was closed by the destructor. (GH 31467)Fixed regression where

`read_pickle()`

raised a`UnicodeDecodeError`

when reading a py27 pickle with`MultiIndex`

column (GH 31988).

**Reindexing/alignment**

Fixed regression in

`Series.align()`

when`other`

is a`DataFrame`

and`method`

is not`None`

(GH 31785)Fixed regression in

`DataFrame.reindex()`

and`Series.reindex()`

when reindexing with (tz-aware) index and`method=nearest`

(GH 26683)Fixed regression in

`DataFrame.reindex_like()`

on a`DataFrame`

subclass raised an`AssertionError`

(GH 31925)Fixed regression in

`DataFrame`

arithmetic operations with mis-matched columns (GH 31623)

**Other**

Fixed regression in joining on

`DatetimeIndex`

or`TimedeltaIndex`

to preserve`freq`

in simple cases (GH 32166)Fixed regression in

`Series.shift()`

with`datetime64`

dtype when passing an integer`fill_value`

(GH 32591)Fixed regression in the repr of an object-dtype

`Index`

with bools and missing values (GH 32146)

## Indexing with nullable boolean arrays#

Previously indexing with a nullable Boolean array containing `NA`

would raise a `ValueError`

, however this is now permitted with `NA`

being treated as `False`

. (GH 31503)

```
In [1]: s = pd.Series([1, 2, 3, 4])
In [2]: mask = pd.array([True, True, False, None], dtype="boolean")
In [3]: s
Out[3]:
0 1
1 2
2 3
3 4
Length: 4, dtype: int64
In [4]: mask
Out[4]:
<BooleanArray>
[True, True, False, <NA>]
Length: 4, dtype: boolean
```

*pandas 1.0.0-1.0.1*

```
>>> s[mask]
Traceback (most recent call last):
...
ValueError: cannot mask with array containing NA / NaN values
```

*pandas 1.0.2*

```
In [5]: s[mask]
Out[5]:
0 1
1 2
Length: 2, dtype: int64
```

## Bug fixes#

**Datetimelike**

Bug in

`Series.astype()`

not copying for tz-naive and tz-aware`datetime64`

dtype (GH 32490)Bug where

`to_datetime()`

would raise when passed`pd.NA`

(GH 32213)Improved error message when subtracting two

`Timestamp`

that result in an out-of-bounds`Timedelta`

(GH 31774)

**Categorical**

Fixed bug where

`Categorical.from_codes()`

improperly raised a`ValueError`

when passed nullable integer codes. (GH 31779)Fixed bug where

`Categorical()`

constructor would raise a`TypeError`

when given a numpy array containing`pd.NA`

. (GH 31927)Bug in

`Categorical`

that would ignore or crash when calling`Series.replace()`

with a list-like`to_replace`

(GH 31720)

**I/O**

Using

`pd.NA`

with`DataFrame.to_json()`

now correctly outputs a null value instead of an empty object (GH 31615)Bug in

`pandas.json_normalize()`

when value in meta path is not iterable (GH 31507)Fixed pickling of

`pandas.NA`

. Previously a new object was returned, which broke computations relying on`NA`

being a singleton (GH 31847)Fixed bug in parquet roundtrip with nullable unsigned integer dtypes (GH 31896).

**Experimental dtypes**

Fixed bug in

`DataFrame.convert_dtypes()`

for columns that were already using the`"string"`

dtype (GH 31731).Fixed bug in

`DataFrame.convert_dtypes()`

for series with mix of integers and strings (GH 32117)Fixed bug in

`DataFrame.convert_dtypes()`

where`BooleanDtype`

columns were converted to`Int64`

(GH 32287)Fixed bug in setting values using a slice indexer with string dtype (GH 31772)

Fixed bug where

`DataFrameGroupBy.first()`

,`SeriesGroupBy.first()`

,`DataFrameGroupBy.last()`

, and`SeriesGroupBy.last()`

would raise a`TypeError`

when groups contained`pd.NA`

in a column of object dtype (GH 32123)Fixed bug where

`DataFrameGroupBy.mean()`

,`DataFrameGroupBy.median()`

,`DataFrameGroupBy.var()`

, and`DataFrameGroupBy.std()`

would raise a`TypeError`

on`Int64`

dtype columns (GH 32219)

**Strings**

Using

`pd.NA`

with`Series.str.repeat()`

now correctly outputs a null value instead of raising error for vector inputs (GH 31632)

**Rolling**

Fixed rolling operations with variable window (defined by time duration) on decreasing time index (GH 32385).

## Contributors#

A total of 25 people contributed patches to this release. People with a “+” by their names contributed a patch for the first time.

Anna Daglis +

Daniel Saxton

Irv Lustig

Jan Škoda

Joris Van den Bossche

Justin Zheng

Kaiqi Dong

Kendall Masse

Marco Gorelli

Matthew Roeschke

MeeseeksMachine

MomIsBestFriend

Pandas Development Team

Pedro Reys +

Prakhar Pandey

Robert de Vries +

Rushabh Vasani

Simon Hawkins

Stijn Van Hoey

Terji Petersen

Tom Augspurger

William Ayd

alimcmaster1

gfyoung

jbrockmendel