Offsets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 New Index methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Google BigQuery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Window functions are now methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Changes to rename . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Additional methods for dt accessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Period Frequency

Offsets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 New Index methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Google BigQuery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Window functions are now methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Changes to rename . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Additional methods for dt accessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Period Frequency

Offsets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 ii 1.6.1.7 New Index methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 1.6.1.8 Google BigQuery Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 1.8.1.1 Window functions are now methods . . . . . . . . . . . . . . . . . . . . . . . . . 111 1.8.1.2 Changes to rename . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 1.10.1.4 Additional methods for dt accessor . . . . . . . . . . . . . . . . . . . . . . . . . 148 1.10.1.5 Period Frequency

Offsets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 1.5.1.7 New Index methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 1.5.1.8 Google BigQuery Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 1.7.1.1 Window functions are now methods . . . . . . . . . . . . . . . . . . . . . . . . . 109 1.7.1.2 Changes to rename . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 1.9.1.4 Additional methods for dt accessor . . . . . . . . . . . . . . . . . . . . . . . . . 146 1.9.1.5 Period Frequency Enhancement

Offsets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 1.8.1.7 New Index methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 1.8.1.8 Google BigQuery Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 1.10.1.1 Window functions are now methods . . . . . . . . . . . . . . . . . . . . . . . . . 140 1.10.1.2 Changes to rename . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 1.12.1.4 Additional methods for dt accessor . . . . . . . . . . . . . . . . . . . . . . . . . 177 1.12.1.5 Period Frequency

explode to split list-like values to rows Series and DataFrame have gained the DataFrame.explode() methods to transform list-likes to individual rows. See section on Exploding list-like column in docs for step attributes (GH25710) • datetime.timezone objects are now supported as arguments to timezone methods and constructors (GH25065) • DataFrame.query() and DataFrame.eval() now supports quoting column Index objects for more. 1.2.8 DataFrame groupby ffill/bfill no longer return group labels The methods ffill, bfill, pad and backfill of DataFrameGroupBy previously included the group labels in the return

explode to split list-like values to rows Series and DataFrame have gained the DataFrame.explode() methods to transform list-likes to individual rows. See section on Exploding list-like column in docs for step attributes (GH25710) • datetime.timezone objects are now supported as arguments to timezone methods and constructors (GH25065) • DataFrame.query() and DataFrame.eval() now supports quoting column Index objects for more. 1.2.8 DataFrame groupby ffill/bfill no longer return group labels The methods ffill, bfill, pad and backfill of DataFrameGroupBy previously included the group labels in the return

set_caption('Summary of results.') Out[48]: Similar methods already exist for other classes in pandas, including DataFrame.pipe(), GroupBy.pipe(), and Resampler when using the openpyxl engine (GH3441) • FrozenList has gained the .union() and .difference() methods. This functionality greatly simpli- fies groupby’s that rely on explicitly excluding certain columns read. (GH24025) • DataFrame.corr() and Series.corr() now accept a callable for generic calculation methods of cor- relation, e.g. histogram intersection (GH22684) • DataFrame.to_string() now accepts decimal

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369 10.10 Vectorized string methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372 10.11 Sorting sortedness with MultiIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468 14.4 Take Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533 17.7 Dispatching to instance methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534 17.8 Flexible apply

dtype="string") In [11]: s Out[11]: 0 abc 1 2 def Length: 3, dtype: string The usual string accessor methods work. Where appropriate, the return type of the Series or columns of a DataFrame will also have string split('b', expand=True).dtypes Out[13]: 0 string 1 string Length: 2, dtype: object String accessor methods returning integers will return a value with Int64Dtype In [14]: s.str.count("a") Out[14]: 0 1 1 extension dtypes StringDtype, BooleanDtype, Int64Dtype, Int32Dtype, etc., that support pd.NA, the methods DataFrame.convert_dtypes() and Series.convert_dtypes() have been introduced. (GH29752) (GH30929)