3.0 compatibility tracker

[loicdiridollou]

This seems like a good starting point with all the changes in 3.0.0 from their release notes.
Not all will need to be taken care of, feel free to mark them as done when addressed.

Updated deprecation policy

• pandas.errors.Pandas4Warning: Warnings which will be enforced in pandas 4.0.
• pandas.errors.Pandas5Warning: Warnings which will be enforced in pandas 5.0.
• pandas.errors.PandasPendingDeprecationWarning: Base class of all warnings which emit a PendingDeprecationWarning, independent of the version they will be enforced.
• pandas.errors.PandasDeprecationWarning: Base class of all warnings which emit a DeprecationWarning, independent of the version they will be enforced.
• pandas.errors.PandasFutureWarning: Base class of all warnings which emit a FutureWarning, independent of the version they will be enforced.

Other enhancements

I/O:

• errors.DtypeWarning improved to include column names when mixed data types are detected (GH 58174)
• DataFrame.to_excel() argument merge_cells now accepts a value of "columns" to only merge MultiIndex column header header cells (GH 35384)
• DataFrame.to_excel() has a new autofilter parameter to add automatic filters to all columns (GH 61194)
• DataFrame.to_excel() now raises a UserWarning when the character count in a cell exceeds Excel’s limitation of 32767 characters (GH 56954)
• read_parquet() accepts to_pandas_kwargs which are forwarded to pyarrow.Table.to_pandas() which enables passing additional keywords to customize the conversion to pandas, such as maps_as_pydicts to read the Parquet map data type as python dictionaries (GH 56842)
• read_spss() now supports kwargs to be passed to pyreadstat (GH 56356)
• read_stata() now returns datetime64 resolutions better matching those natively stored in the stata format (GH 55642)
• DataFrame.to_csv() and Series.to_csv() now support f-strings (e.g., "{:.6f}") for the float_format parameter, in addition to the % format strings and callables (GH 49580)
• DataFrame.to_json() now encodes Decimal as strings instead of floats (GH 60698)
• Added "delete_rows" option to if_exists argument in DataFrame.to_sql() deleting all records of the table before inserting data (GH 37210).
• Added support to read and write from and to Apache Iceberg tables with the new read_iceberg() and DataFrame.to_iceberg() functions (GH 61383)
• Errors occurring during SQL I/O will now throw a generic DatabaseError instead of the raw Exception type from the underlying driver manager library (GH 60748)
• Restore support for reading Stata 104-format and enable reading 103-format dta files (GH 58554)
• Support reading Stata 102-format (Stata 1) dta files (GH 58978)
• Support reading Stata 110-format (Stata 7) dta files (GH 47176)
• Support reading value labels from Stata 108-format (Stata 6) and earlier files (GH 58154)

Groupby/resample/rolling:

• pandas.NamedAgg now supports passing *args and **kwargs to calls of aggfunc (GH 58283)
• DataFrameGroupBy and SeriesGroupBy methods sum, mean, median, prod, min, max, std, var and sem now accept skipna parameter (GH 15675)
• DataFrameGroupBy.transform(), SeriesGroupBy.transform(), DataFrameGroupBy.agg(), SeriesGroupBy.agg(), RollingGroupby.apply(), ExpandingGroupby.apply(), Rolling.apply(), Expanding.apply(), DataFrame.apply() with engine="numba" now supports positional arguments passed as kwargs (GH 58995)
• DataFrameGroupBy.transform(), SeriesGroupBy.transform(), DataFrameGroupBy.agg(), SeriesGroupBy.agg(), SeriesGroupBy.apply(), DataFrameGroupBy.apply() now support kurt (GH 40139)
• Rolling.aggregate(), Expanding.aggregate() and ExponentialMovingWindow.aggregate() now accept NamedAgg aggregations through **kwargs (GH 28333)
• Added Rolling.first(), Rolling.last(), Expanding.first(), and Expanding.last() (GH 33155)
• Added Rolling.nunique() and Expanding.nunique() (GH 26958)
• Added Rolling.pipe() and Expanding.pipe() (GH 57076)

Reshaping:

• pandas.merge() propagates the attrs attribute to the result if all inputs have identical attrs, as has so far already been the case for pandas.concat().
• pandas.merge() now validates the how parameter input (merge type) (GH 59435)
• pandas.merge(), DataFrame.merge() and DataFrame.join() now support anti joins (left_anti and right_anti) in the how parameter (GH 42916)
• DataFrame.pivot_table() and pivot_table() now allow the passing of keyword arguments to aggfunc through **kwargs (GH 57884)
• pandas.concat() will raise a ValueError when ignore_index=True and keys is not None (GH 59274)
• Improve error reporting through outputting the first few duplicates when merge() validation fails (GH 62742)

Missing:

• DataFrame.fillna() and Series.fillna() can now accept value=None; for non-object dtype the corresponding NA value will be used (GH 57723)
• Added support for axis=1 with dict or Series arguments in DataFrame.fillna() (GH 4514)

Numeric:

• DataFrame.agg() called with axis=1 and a func which relabels the result index now raises a NotImplementedError (GH 58807).
• DataFrame.corrwith() now accepts min_periods as optional arguments, as in DataFrame.corr() and Series.corr() (GH 9490)
• DataFrame.cummin(), DataFrame.cummax(), DataFrame.cumprod() and DataFrame.cumsum() methods now have a numeric_only parameter (GH 53072)
• DataFrame.ewm() now allows adjust=False when times is provided (GH 54328)
• Series.cummin() and Series.cummax() now supports CategoricalDtype (GH 52335)
• Series.map() can now accept kwargs to pass on to func (GH 59814)
• Series.nlargest() uses stable sort internally and will preserve original ordering in the case of equality (GH 55767)
• Series.round() now supports object dtypes when the underlying Python objects implement round (GH 63444)
• Support passing a Iterable[Hashable] input to DataFrame.drop_duplicates() (GH 59237)

Strings:

• Series.str.get_dummies() now accepts a dtype parameter to specify the dtype of the resulting DataFrame (GH 47872)
• Added Series.str.isascii() (GH 59091)
• Allow dictionaries to be passed to Series.str.replace() via pat parameter (GH 51748)

Datetimelike:

• Easter has gained a new constructor argument method which specifies the method used to calculate Easter — for example, Orthodox Easter (GH 61665)
• Holiday constructor argument days_of_week will raise a ValueError when type is something other than None or tuple (GH 61658)
• Holiday has gained the constructor argument and field exclude_dates to exclude specific datetimes from a custom holiday calendar (GH 54382)
• Added half-year offset classes HalfYearBegin, HalfYearEnd, BHalfYearBegin and BHalfYearEnd (GH 60928)
• Improved deprecation message for offset aliases (GH 60820)
• Multiplying two DateOffset objects will now raise a TypeError instead of a RecursionError (GH 59442)

Indexing:

• DataFrame.iloc() and Series.iloc() now support boolean masks in getitem for more consistent indexing behavior (GH 60994)
• Index.get_loc() now accepts also subclasses of tuple as keys (GH 57922)

Styler / output formatting:

• Styler.set_tooltips() provides alternative method to storing tooltips by using title attribute of td elements. (GH 56981)
• Added Styler.to_typst() to write Styler objects to file, buffer or string in Typst format (GH 57617)
• Styler.format_index_names() can now be used to format the index and column names (GH 48936 and GH 47489)
• frozenset elements in pandas objects are now natively printed (GH 60690)

Typing:

• pandas.api.typing.FrozenList is available for typing the outputs of MultiIndex.names, MultiIndex.codes and MultiIndex.levels (GH 58237)
• pandas.api.typing.NoDefault is available for typing no_default (GH 60696)
• pandas.api.typing.SASReader is available for typing the output of read_sas() (GH 55689)
• Many type aliases are now exposed in the new submodule pandas.api.typing.aliases (GH 55231)

Plotting:

• Series.plot() now correctly handle the ylabel parameter for pie charts, allowing for explicit control over the y-axis label (GH 58239)
• Added missing parameter weights in DataFrame.plot.kde() for the estimation of the PDF (GH 59337)
• DataFrame.plot.scatter() argument c now accepts a column of strings, where rows with the same string are colored identically (GH 16827 and GH 16485)

ExtensionArray:

• ArrowDtype now supports pyarrow.JsonType (GH 60958)
• Series.rank() and DataFrame.rank() with numpy-nullable dtypes preserve NA values and return UInt64 dtype where appropriate instead of casting NA to NaN with float64 dtype (GH 62043)
• Improve the resulting dtypes in DataFrame.where() and DataFrame.mask() with ExtensionDtype other (GH 62038)

Other:

• set_option() now accepts a dictionary of options, simplifying configuration of multiple settings at once (GH 61093)
• DataFrame.apply() supports using third-party execution engines like the Bodo.ai JIT compiler (GH 60668)
• Series.map() now accepts an engine parameter to allow execution with a third-party execution engine (GH 61125)
• Support passing a Series input to json_normalize() that retains the Index (GH 51452)
• Users can globally disable any PerformanceWarning by setting the option mode.performance_warnings to False (GH 56920)

Packaging:

• Switched wheel upload to PyPI Trusted Publishing (OIDC) for release-tag pushes in wheels.yml. (GH 61718)
• Wheels are now available for Windows ARM64 architecture (GH 61462)
• Wheels are now available for free-threading Python builds on Windows (in addition to the other platforms) (GH 61463)

Other API changes

• 3rd party py.path objects are no longer explicitly supported in IO methods. Use pathlib.Path objects instead (GH 57091)
• read_table()’s parse_dates argument defaults to None to improve consistency with read_csv() (GH 57476)
• Period.to_timestamp() and PeriodIndex.to_timestamp() now give microsecond-unit objects when possible, and nanosecond-unit objects in other cases. This affects the actual value of Period.end_time() and PeriodIndex.end_time() (GH 56164)
• All classes inheriting from builtin tuple (including types created with collections.namedtuple()) are now hashed and compared as builtin tuple during indexing operations (GH 57922)
• Made dtype a required argument in ExtensionArray._from_sequence_of_strings() (GH 56519)
• Passing a Series input to json_normalize() will now retain the Series Index, previously output had a new RangeIndex (GH 51452)
• Pickle and HDF (.h5) files created with Python 2 are no longer explicitly supported (GH 57387)
• Pickled objects from pandas version less than 1.0.0 are no longer supported (GH 57155)
• Removed Index.sort() which always raised a TypeError. This attribute is not defined and will raise an AttributeError (GH 59283)
• Unused dtype argument has been removed from the MultiIndex constructor (GH 60962)
• Updated DataFrame.to_excel() so that the output spreadsheet has no styling. Custom styling can still be done using Styler.to_excel() (GH 54154)
• When comparing the indexes in testing.assert_series_equal(), check_exact defaults to True if an Index is of integer dtype. (GH 57386)
• Index set operations (like union or intersection) will now ignore the dtype of an empty RangeIndex or empty Index with object dtype when determining the dtype of the resulting Index (GH 60797)
• IncompatibleFrequency now subclasses TypeError instead of ValueError. As a result, joins with mismatched frequencies now cast to object like other non-comparable joins, and arithmetic with indexes with mismatched frequencies align (GH 55782)
• Series “flex” methods like Series.add() no longer allow passing a DataFrame for other; use the DataFrame reversed method instead (GH 46179)
• date_range() and timedelta_range() no longer default to unit="ns", instead will infer a unit from the start, end, and freq parameters. Explicitly specify a desired unit to override these (GH 59031)
• CategoricalIndex.append() no longer attempts to cast different-dtype indexes to the caller’s dtype (GH 41626)
• ExtensionDtype.construct_array_type() is now a regular method instead of a classmethod (GH 58663)
• Arithmetic operations between a Series, Index, or ExtensionArray with a list now consistently wrap that list with an array equivalent to Series(my_list).array. To do any other kind of type inference or casting, do so explicitly before operating (GH 62552)
• Comparison operations between Index and Series now consistently return Series regardless of which object is on the left or right (GH 36759)
• NumPy functions like np.isinf that return a bool dtype when called on a Index object now return a bool-dtype Index instead of np.ndarray (GH 52676)
• Methods that can operate in-place (replace(), fillna(), ffill(), bfill(), interpolate(), where(), mask(), clip()) now return the modified DataFrame or Series (self) instead of None when inplace=True (GH 63207)
• All Index constructors now copy numpy.ndarray and ExtensionArray inputs by default when copy=None, consistent with Series behavior (GH 63388)

[loicdiridollou]

Deprecations

Copy keyword

The copy keyword argument in the following methods is deprecated and will be removed in a future version. (GH 57347)

• DataFrame.truncate() / Series.truncate()
• DataFrame.tz_convert() / Series.tz_convert()
• DataFrame.tz_localize() / Series.tz_localize()
• DataFrame.infer_objects() / Series.infer_objects()
• DataFrame.align() / Series.align()
• DataFrame.astype() / Series.astype()
• DataFrame.reindex() / Series.reindex()
• DataFrame.reindex_like() / Series.reindex_like()
• DataFrame.set_axis() / Series.set_axis()
• DataFrame.to_period() / Series.to_period()
• DataFrame.to_timestamp() / Series.to_timestamp()
• DataFrame.rename() / Series.rename()
• DataFrame.transpose()
• DataFrame.swaplevel()
• DataFrame.merge() / pd.merge()

Copy-on-Write utilizes a lazy copy mechanism that defers copying the data until necessary. Use .copy to trigger an eager copy. The copy keyword has no effect starting with 3.0, so it can be safely removed from your code.

Other Deprecations:

• Deprecated core.internals.api.make_block(), use public APIs instead (GH 56815)
• Deprecated DataFrameGroupby.corrwith() (GH 57158)
• Deprecated Timestamp.utcfromtimestamp(), use Timestamp.fromtimestamp(ts, "UTC") instead (GH 56680)
• Deprecated Timestamp.utcnow(), use Timestamp.now("UTC") instead (GH 56680)
• Deprecated pd.core.internals.api.maybe_infer_ndim (GH 40226)
• Deprecated allowing constructing or casting to Categorical with non-NA values that are not present in specified dtype.categories (GH 40996)
• Deprecated allowing non-keyword arguments in DataFrame.all(), DataFrame.min(), DataFrame.max(), DataFrame.sum(), DataFrame.prod(), DataFrame.mean(), DataFrame.median(), DataFrame.sem(), DataFrame.var(), DataFrame.std(), DataFrame.skew(), DataFrame.kurt(), Series.all(), Series.min(), Series.max(), Series.sum(), Series.prod(), Series.mean(), Series.median(), Series.sem(), Series.var(), Series.std(), Series.skew(), and Series.kurt(). (GH 57087)
• Deprecated allowing non-keyword arguments in DataFrame.groupby() and Series.groupby() except by and level. (GH 62102)
• Deprecated allowing non-keyword arguments in Series.to_markdown() except buf. (GH 57280)
• Deprecated allowing non-keyword arguments in Series.to_string() except buf. (GH 57280)
• Deprecated behavior of DataFrameGroupBy.groups() and SeriesGroupBy.groups() returning scalar dictionary keys when grouping by list with a single element. The dictionary keys return will be tuples in a future version. (GH 58858)
• Deprecated behavior of Series.dt.to_pytimedelta(), in a future version this will return a Series containing python datetime.timedelta objects instead of an ndarray of timedelta; this matches the behavior of other Series.dt() properties. (GH 57463)
• Deprecated converting object-dtype columns of datetime.datetime objects to datetime64 when writing to stata (GH 56536)
• Deprecated lowercase strings d, b and c denoting frequencies in Day, BusinessDay and CustomBusinessDay in favour of D, B and C (GH 58998)
• Deprecated lowercase strings w, w-mon, w-tue, etc. denoting frequencies in Week in favour of W, W-MON, W-TUE, etc. (GH 58998)
• Deprecated parameter method in DataFrame.reindex_like() / Series.reindex_like() (GH 58667)
• Deprecated strings w, d, MIN, MS, US and NS denoting units in Timedelta in favour of W, D, min, ms, us and ns (GH 59051)
• Deprecated the arg parameter of Series.map(); pass the added func argument instead. (GH 61260)
• Deprecated the verify_integrity keyword in DataFrame.set_index(); directly check the result for obj.index.is_unique instead (GH 62919)
• Deprecated the keyword check_datetimelike_compat in testing.assert_frame_equal() and testing.assert_series_equal() (GH 55638)
• Deprecated using epoch date format in DataFrame.to_json() and Series.to_json(), use iso instead. (GH 57063)
• Deprecated allowing fill_value that cannot be held in the original dtype (excepting NA values for integer and bool dtypes) in Series.unstack() and DataFrame.unstack() (GH 12189, GH 53868)
• Deprecated allowing fill_value that cannot be held in the original dtype (excepting NA values for integer and bool dtypes) in Series.shift() and DataFrame.shift() (GH 53802)
• Deprecated allowing strings representing full dates in DataFrame.at_time() and Series.at_time() (GH 50839)
• Deprecated backward-compatibility behavior for DataFrame.select_dtypes() matching str dtype when np.object_ is specified (GH 61916)
• Deprecated option future.no_silent_downcasting, as it is no longer used. In a future version accessing this option will raise (GH 59502)
• Deprecated passing non-Index types to Index.join(); explicitly convert to Index first (GH 62897)
• Deprecated silent casting of non-datetime other to datetime in Series.combine_first() (GH 62931)
• Deprecated silently casting strings to Timedelta in binary operations with Timedelta (GH 59653)
• Deprecated slicing on a Series or DataFrame with a DatetimeIndex using a datetime.date object, explicitly cast to Timestamp instead (GH 35830)
• Deprecated support for the Dataframe Interchange Protocol (GH 56732)
• Deprecated the inplace keyword from Resampler.interpolate(), as passing True raises AttributeError (GH 58690)

Other Removals

• DataFrameGroupBy.idxmin(), DataFrameGroupBy.idxmax(), SeriesGroupBy.idxmin(), and SeriesGroupBy.idxmax() will now raise a ValueError when a group has all NA values, or when used with skipna=False and any NA value is encountered (GH 10694, GH 57745)
• concat() no longer ignores empty objects when determining output dtypes (GH 39122)
• concat() with all-NA entries no longer ignores the dtype of those entries when determining the result dtype (GH 40893)
• read_excel(), read_json(), read_html(), and read_xml() no longer accept raw string or byte representation of the data. That type of data must be wrapped in a StringIO or BytesIO (GH 53767)
• to_datetime() with a unit specified no longer parses strings into floats, instead parses them the same way as without unit (GH 50735)
• SeriesGroupBy.agg() no longer pins the name of the group to the input passed to the provided func (GH 51703)
• DataFrame.groupby() with as_index=False and aggregation methods will no longer exclude from the result the groupings that do not arise from the input (GH 49519)
• ExtensionArray._reduce() now requires a keepdims: bool = False parameter in the signature (GH 52788)
• Series.dt.to_pydatetime() now returns a Series of datetime.datetime objects (GH 52459)
• All arguments except name in Index.rename() are now keyword only (GH 56493)
• All arguments except the first path-like argument in IO writers are now keyword only (GH 54229)
• Changed behavior of Series.getitem() and Series.setitem() to always treat integer keys as labels, never as positional, consistent with DataFrame behavior (GH 50617)
• Changed behavior of Series.getitem(), Series.setitem(), DataFrame.getitem(), DataFrame.setitem() with an integer slice on objects with a floating-dtype index. This is now treated as positional indexing (GH 49612)
• Disallow a callable argument to Series.iloc() to return a tuple (GH 53769)
• Disallow allowing logical operations (||, &, ^) between pandas objects and dtype-less sequences (e.g. list, tuple); wrap the objects in Series, Index, or np.array first instead (GH 52264)
• Disallow automatic casting to object in Series logical operations (&, ^, ||) between series with mismatched indexes and dtypes other than object or bool (GH 52538)
• Disallow calling Series.replace() or DataFrame.replace() without a value and with non-dict-like to_replace (GH 33302)
• Disallow constructing a arrays.SparseArray with scalar data (GH 53039)
• Disallow indexing an Index with a boolean indexer of length zero, it now raises ValueError (GH 55820)
• Disallow non-standard (np.ndarray, Index, ExtensionArray, or Series) to isin(), unique(), factorize() (GH 52986)
• Disallow passing a pandas type to Index.view() (GH 55709)
• Disallow units other than “s”, “ms”, “us”, “ns” for datetime64 and timedelta64 dtypes in array() (GH 53817)
• Removed Block, DatetimeTZBlock, ExtensionBlock, create_block_manager_from_blocks from pandas.core.internals and pandas.core.internals.api (GH 55139)
• Removed fastpath keyword in Categorical constructor (GH 20110)
• Removed freq keyword from PeriodArray constructor, use “dtype” instead (GH 52462)
• Removed kind keyword in Series.resample() and DataFrame.resample() (GH 58125)
• Removed alias arrays.PandasArray for arrays.NumpyExtensionArray (GH 53694)
• Removed deprecated method and limit keywords from Series.replace() and DataFrame.replace() (GH 53492)
• Removed extension test classes BaseNoReduceTests, BaseNumericReduceTests, BaseBooleanReduceTests (GH 54663)
• Removed the closed and normalize keywords in DatetimeIndex constructor (GH 52628)
• Removed the deprecated delim_whitespace keyword in read_csv() and read_table(), use sep=r"\s+" instead (GH 55569)
• Require SparseDtype.fill_value() to be a valid value for the SparseDtype.subtype() (GH 53043)
• Stopped automatically casting non-datetimelike values (mainly strings) in Series.isin() and Index.isin() with datetime64, timedelta64, and PeriodDtype dtypes (GH 53111)
• Stopped performing dtype inference in Index, Series and DataFrame constructors when given a pandas object (Series, Index, ExtensionArray), call .infer_objects on the input to keep the current behavior (GH 56012)
• Stopped performing dtype inference when setting a Index into a DataFrame (GH 56102)
• Stopped performing dtype inference with in Index.insert() with object-dtype index; this often affects the index/columns that result when setting new entries into an empty Series or DataFrame (GH 51363)
• Removed the closed and unit keywords in TimedeltaIndex constructor (GH 52628, GH 55499)
• All arguments in Index.sort_values() are now keyword only (GH 56493)
• All arguments in Series.to_dict() are now keyword only (GH 56493)
• Changed the default value of na_action in Categorical.map() to None (GH 51645)
• Changed the default value of observed in DataFrame.groupby() and Series.groupby() to True (GH 51811)
• Enforce banning of upcasting in in-place setitem-like operations; see PDEP6 (GH 59007)
• Enforce deprecation in testing.assert_series_equal() and testing.assert_frame_equal() with object dtype and mismatched null-like values, which are now considered not-equal (GH 18463)
• Enforced deprecation all and any reductions with datetime64, DatetimeTZDtype, and PeriodDtype dtypes (GH 58029)
• Enforced deprecation allowing non-bool and NA values for na in str.contains(), str.startswith(), and str.endswith() (GH 59615)
• Enforced deprecation disallowing float for the periods argument in date_range(), period_range(), timedelta_range(), interval_range(), (GH 56036)
• Enforced deprecation disallowing parsing datetimes with mixed time zones unless user passes utc=True to to_datetime() (GH 57275)
• Enforced deprecation in Series.value_counts() and Index.value_counts() with object dtype performing dtype inference on the .index of the result (GH 56161)
• Enforced deprecation of DataFrameGroupBy.get_group() and SeriesGroupBy.get_group() allowing the name argument to be a non-tuple when grouping by a list of length 1 (GH 54155)
• Enforced deprecation of Series.interpolate() and DataFrame.interpolate() for object-dtype (GH 57820)
• Enforced deprecation of offsets.Tick.delta(), use pd.Timedelta(obj) instead (GH 55498)
• Enforced deprecation of axis=None acting the same as axis=0 in the DataFrame reductions sum, prod, std, var, and sem, passing axis=None will now reduce over both axes; this is particularly the case when doing e.g. numpy.sum(df) (GH 21597)
• Enforced deprecation of core.internals member DatetimeTZBlock (GH 58467)
• Enforced deprecation of date_parser in read_csv(), read_table(), read_fwf(), and read_excel() in favour of date_format (GH 50601)
• Enforced deprecation of keep_date_col keyword in read_csv() (GH 55569)
• Enforced deprecation of quantile keyword in Rolling.quantile() and Expanding.quantile(), renamed to q instead. (GH 52550)
• Enforced deprecation of argument infer_datetime_format in read_csv(), as a strict version of it is now the default (GH 48621)
• Enforced deprecation of combining parsed datetime columns in read_csv() in parse_dates (GH 55569)
• Enforced deprecation of non-standard (np.ndarray, ExtensionArray, Index, or Series) argument to api.extensions.take() (GH 52981)
• Enforced deprecation of parsing system timezone strings to tzlocal, which depended on system timezone, pass the tz keyword instead (GH 50791)
• Enforced deprecation of passing a dictionary to SeriesGroupBy.agg() (GH 52268)
• Enforced deprecation of string AS denoting frequency in YearBegin and strings AS-DEC, AS-JAN, etc. denoting annual frequencies with various fiscal year starts (GH 57793)
• Enforced deprecation of string A denoting frequency in YearEnd and strings A-DEC, A-JAN, etc. denoting annual frequencies with various fiscal year ends (GH 57699)
• Enforced deprecation of string BAS denoting frequency in BYearBegin and strings BAS-DEC, BAS-JAN, etc. denoting annual frequencies with various fiscal year starts (GH 57793)
• Enforced deprecation of string BA denoting frequency in BYearEnd and strings BA-DEC, BA-JAN, etc. denoting annual frequencies with various fiscal year ends (GH 57793)
• Enforced deprecation of strings H, BH, and CBH denoting frequencies in Hour, BusinessHour, CustomBusinessHour (GH 59143)
• Enforced deprecation of strings H, BH, and CBH denoting units in Timedelta (GH 59143)
• Enforced deprecation of strings T, L, U, and N denoting frequencies in Minute, Milli, Micro, Nano (GH 57627)
• Enforced deprecation of strings T, L, U, and N denoting units in Timedelta (GH 57627)
• Enforced deprecation of the behavior of concat() when len(keys) != len(objs) would truncate to the shorter of the two. Now this raises a ValueError (GH 43485)
• Enforced deprecation of the behavior of DataFrame.replace() and Series.replace() with CategoricalDtype that would introduce new categories. (GH 58270)
• Enforced deprecation of the behavior of Series.argsort() in the presence of NA values (GH 58232)
• Enforced deprecation of values “pad”, “ffill”, “bfill”, and “backfill” for Series.interpolate() and DataFrame.interpolate() (GH 57869)
• Enforced deprecation removing Categorical.to_list(), use obj.tolist() instead (GH 51254)
• Enforced silent-downcasting deprecation for all relevant methods (GH 54710)
• In DataFrame.stack(), the default value of future_stack is now True; specifying False will raise a FutureWarning (GH 55448)
• Iterating over a DataFrameGroupBy or SeriesGroupBy will return tuples of length 1 for the groups when grouping by level a list of length 1 (GH 50064)
• Methods apply, agg, and transform will no longer replace NumPy functions (e.g. np.sum) and built-in functions (e.g. min) with the equivalent pandas implementation; use string aliases (e.g. "sum" and "min") if you desire to use the pandas implementation (GH 53974)
• Passing both freq and fill_value in DataFrame.shift() and Series.shift() and DataFrameGroupBy.shift() now raises a ValueError (GH 54818)
• Removed DataFrameGroupBy.quantile() and SeriesGroupBy.quantile() supporting bool dtype (GH 53975)
• Removed DateOffset.is_anchored() and offsets.Tick.is_anchored() (GH 56594)
• Removed DataFrame.applymap, Styler.applymap and Styler.applymap_index (GH 52364)
• Removed DataFrame.bool and Series.bool (GH 51756)
• Removed DataFrame.first and DataFrame.last (GH 53710)
• Removed DataFrame.swapaxes and Series.swapaxes (GH 51946)
• Removed DataFrameGroupBy.grouper and SeriesGroupBy.grouper (GH 56521)
• Removed DataFrameGroupby.fillna and SeriesGroupBy.fillna` (GH 55719)
• Removed Index.format, use Index.astype() with str or Index.map() with a formatter function instead (GH 55439)
• Removed Resample.fillna (GH 55719)
• Removed Series.int and Series.float. Call int(Series.iloc[0]) or float(Series.iloc[0]) instead. (GH 51131)
• Removed Series.ravel (GH 56053)
• Removed Series.view (GH 56054)
• Removed StataReader.close (GH 49228)
• Removed _data from DataFrame, Series, arrays.ArrowExtensionArray (GH 52003)
• Removed axis argument from DataFrame.groupby(), Series.groupby(), DataFrame.rolling(), Series.rolling(), DataFrame.resample(), and Series.resample() (GH 51203)
• Removed axis argument from all groupby operations (GH 50405)
• Removed convert_dtype from Series.apply() (GH 52257)
• Removed method, limit fill_axis and broadcast_axis keywords from DataFrame.align() (GH 51968)
• Removed pandas.api.types.is_interval and pandas.api.types.is_period, use isinstance(obj, pd.Interval) and isinstance(obj, pd.Period) instead (GH 55264)
• Removed pandas.io.sql.execute (GH 50185)
• Removed pandas.value_counts, use Series.value_counts() instead (GH 53493)
• Removed read_gbq and DataFrame.to_gbq. Use pandas_gbq.read_gbq and pandas_gbq.to_gbq instead https://pandas-gbq.readthedocs.io/en/latest/api.html (GH 55525)
• Removed use_nullable_dtypes from read_parquet() (GH 51853)
• Removed year, month, quarter, day, hour, minute, and second keywords in the PeriodIndex constructor, use PeriodIndex.from_fields() instead (GH 55960)
• Removed argument limit from DataFrame.pct_change(), Series.pct_change(), DataFrameGroupBy.pct_change(), and SeriesGroupBy.pct_change(); the argument method must be set to None and will be removed in a future version of pandas (GH 53520)
• Removed deprecated argument obj in DataFrameGroupBy.get_group() and SeriesGroupBy.get_group() (GH 53545)
• Removed deprecated behavior of Series.agg() using Series.apply() (GH 53325)
• Removed deprecated keyword method on Series.fillna(), DataFrame.fillna() (GH 57760)
• Removed option mode.use_inf_as_na, convert inf entries to NaN before instead (GH 51684)
• Removed support for DataFrame in DataFrame.from_records() (GH 51697)
• Removed support for errors="ignore" in to_datetime(), to_timedelta() and to_numeric() (GH 55734)
• Removed support for slice in DataFrame.take() (GH 51539)
• Removed the ArrayManager (GH 55043)
• Removed the fastpath argument from the Series constructor (GH 55466)
• Removed the is_boolean, is_integer, is_floating, holds_integer, is_numeric, is_categorical, is_object, and is_interval attributes of Index (GH 50042)
• Removed the ordinal keyword in PeriodIndex, use PeriodIndex.from_ordinals() instead (GH 55960)
• Removed unused arguments *args and **kwargs in Resampler methods (GH 50977)
• Unrecognized timezones when parsing strings to datetimes now raises a ValueError (GH 51477)
• Removed the Grouper attributes ax, groups, indexer, and obj (GH 51206, GH 51182)
• Removed deprecated keyword verbose on read_csv() and read_table() (GH 56556)
• Removed the method keyword in ExtensionArray.fillna(), implement ExtensionArray._pad_or_backfill instead (GH 53621)
• Removed the attribute dtypes from DataFrameGroupBy (GH 51997)
• Enforced deprecation of argmin, argmax, idxmin, and idxmax returning a result when skipna=False and an NA value is encountered or all values are NA values; these operations will now raise in such cases (GH 33941, GH 51276)
• Enforced deprecation of storage option “pyarrow_numpy” for StringDtype (GH 60152)
• Removed specifying include_groups=True in DataFrameGroupBy.apply() and Resampler.apply() (GH 7155)