DEPR: Remove how, fill_method, and limit from resample (#30139)

doc/source/whatsnew/v1.0.0.rst

@@ -600,6 +600,7 @@ or ``matplotlib.Axes.plot``. See :ref:`plotting.formatters` for more.
 - In :func:`concat` the default value for ``sort`` has been changed from ``None`` to ``False`` (:issue:`20613`)
 - Removed previously deprecated "raise_conflict" argument from :meth:`DataFrame.update`, use "errors" instead (:issue:`23585`)
 - Removed previously deprecated keyword "n" from :meth:`DatetimeIndex.shift`, :meth:`TimedeltaIndex.shift`, :meth:`PeriodIndex.shift`, use "periods" instead (:issue:`22458`)
+- Removed previously deprecated keywords ``how``, ``fill_method``, and ``limit`` from :meth:`DataFrame.resample` (:issue:`30139`)
 - Passing an integer to :meth:`Series.fillna` or :meth:`DataFrame.fillna` with ``timedelta64[ns]`` dtype now raises ``TypeError`` (:issue:`24694`)
 - Passing multiple axes to :meth:`DataFrame.dropna` is no longer supported (:issue:`20995`)
 - Removed previously deprecated :meth:`Series.nonzero`, use `to_numpy().nonzero()` instead (:issue:`24048`)

pandas/core/generic.py

@@ -7728,15 +7728,12 @@ def between_time(
     def resample(
         self,
         rule,
-        how: Optional[str] = None,
         axis=0,
-        fill_method: Optional[str] = None,
         closed: Optional[str] = None,
         label: Optional[str] = None,
         convention: str = "start",
         kind: Optional[str] = None,
         loffset=None,
-        limit: Optional[int] = None,
         base: int = 0,
         on=None,
         level=None,
@@ -7753,22 +7750,10 @@ def resample(
         ----------
         rule : DateOffset, Timedelta or str
             The offset string or object representing target conversion.
-        how : str
-            Method for down/re-sampling, default to 'mean' for downsampling.
-
-            .. deprecated:: 0.18.0
-               The new syntax is ``.resample(...).mean()``, or
-               ``.resample(...).apply(<func>)``
         axis : {0 or 'index', 1 or 'columns'}, default 0
             Which axis to use for up- or down-sampling. For `Series` this
             will default to 0, i.e. along the rows. Must be
             `DatetimeIndex`, `TimedeltaIndex` or `PeriodIndex`.
-        fill_method : str, default None
-            Filling method for upsampling.
-
-            .. deprecated:: 0.18.0
-               The new syntax is ``.resample(...).<func>()``,
-               e.g. ``.resample(...).pad()``
         closed : {'right', 'left'}, default None
             Which side of bin interval is closed. The default is 'left'
             for all frequency offsets except for 'M', 'A', 'Q', 'BM',
@@ -7786,10 +7771,6 @@ def resample(
             By default the input representation is retained.
         loffset : timedelta, default None
             Adjust the resampled time labels.
-        limit : int, default None
-            Maximum size gap when reindexing with `fill_method`.
-
-            .. deprecated:: 0.18.0
         base : int, default 0
             For frequencies that evenly subdivide 1 day, the "origin" of the
             aggregated intervals. For example, for '5min' frequency, base could
@@ -8021,10 +8002,10 @@ def resample(
         2000-01-04     36      90
         """
 
-        from pandas.core.resample import resample, _maybe_process_deprecations
+        from pandas.core.resample import resample
 
         axis = self._get_axis_number(axis)
-        r = resample(
+        return resample(
             self,
             freq=rule,
             label=label,
@@ -8037,9 +8018,6 @@ def resample(
             key=on,
             level=level,
         )
-        return _maybe_process_deprecations(
-            r, how=how, fill_method=fill_method, limit=limit
-        )
 
     def first(self, offset):
         """

pandas/core/resample.py

@@ -2,7 +2,6 @@
 from datetime import timedelta
 from textwrap import dedent
 from typing import Dict, no_type_check
-import warnings
 
 import numpy as np
 
@@ -953,58 +952,6 @@ def h(self, _method=method):
     setattr(Resampler, method, h)
 
 
-def _maybe_process_deprecations(r, how=None, fill_method=None, limit=None):
-    """
-    Potentially we might have a deprecation warning, show it
-    but call the appropriate methods anyhow.
-    """
-
-    if how is not None:
-
-        # .resample(..., how='sum')
-        if isinstance(how, str):
-            method = "{0}()".format(how)
-
-            # .resample(..., how=lambda x: ....)
-        else:
-            method = ".apply(<func>)"
-
-        # if we have both a how and fill_method, then show
-        # the following warning
-        if fill_method is None:
-            warnings.warn(
-                "how in .resample() is deprecated\n"
-                "the new syntax is "
-                ".resample(...).{method}".format(method=method),
-                FutureWarning,
-                stacklevel=3,
-            )
-        r = r.aggregate(how)
-
-    if fill_method is not None:
-
-        # show the prior function call
-        method = "." + method if how is not None else ""
-
-        args = "limit={0}".format(limit) if limit is not None else ""
-        warnings.warn(
-            "fill_method is deprecated to .resample()\n"
-            "the new syntax is .resample(...){method}"
-            ".{fill_method}({args})".format(
-                method=method, fill_method=fill_method, args=args
-            ),
-            FutureWarning,
-            stacklevel=3,
-        )
-
-        if how is not None:
-            r = getattr(r, fill_method)(limit=limit)
-        else:
-            r = r.aggregate(fill_method, limit=limit)
-
-    return r
-
-
 class _GroupByMixin(GroupByMixin):
     """
     Provide the groupby facilities.
@@ -1342,8 +1289,7 @@ def get_resampler_for_grouping(
 
     tg = TimeGrouper(freq=rule, **kwargs)
     resampler = tg._get_resampler(groupby.obj, kind=kind)
-    r = resampler._get_resampler_for_grouping(groupby=groupby)
-    return _maybe_process_deprecations(r, how=how, fill_method=fill_method, limit=limit)
+    return resampler._get_resampler_for_grouping(groupby=groupby)
 
 
 class TimeGrouper(Grouper):

pandas/tests/resample/test_base.py

@@ -207,7 +207,8 @@ def test_resample_empty_dtypes(index, dtype, resample_method):
 
 
 @all_ts
-def test_resample_loffset_arg_type(frame, create_index):
+@pytest.mark.parametrize("arg", ["mean", {"value": "mean"}, ["mean"]])
+def test_resample_loffset_arg_type(frame, create_index, arg):
     # GH 13218, 15002
     df = frame
     expected_means = [df.values[i : i + 2].mean() for i in range(0, len(df.values), 2)]
@@ -220,26 +221,18 @@ def test_resample_loffset_arg_type(frame, create_index):
     expected_index += timedelta(hours=2)
     expected = DataFrame({"value": expected_means}, index=expected_index)
 
-    for arg in ["mean", {"value": "mean"}, ["mean"]]:
+    result_agg = df.resample("2D", loffset="2H").agg(arg)
 
-        result_agg = df.resample("2D", loffset="2H").agg(arg)
+    if isinstance(arg, list):
+        expected.columns = pd.MultiIndex.from_tuples([("value", "mean")])
 
-        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False):
-            result_how = df.resample("2D", how=arg, loffset="2H")
-
-        if isinstance(arg, list):
-            expected.columns = pd.MultiIndex.from_tuples([("value", "mean")])
-
-        # GH 13022, 7687 - TODO: fix resample w/ TimedeltaIndex
-        if isinstance(expected.index, TimedeltaIndex):
-            msg = "DataFrame are different"
-            with pytest.raises(AssertionError, match=msg):
-                tm.assert_frame_equal(result_agg, expected)
-            with pytest.raises(AssertionError, match=msg):
-                tm.assert_frame_equal(result_how, expected)
-        else:
+    # GH 13022, 7687 - TODO: fix resample w/ TimedeltaIndex
+    if isinstance(expected.index, TimedeltaIndex):
+        msg = "DataFrame are different"
+        with pytest.raises(AssertionError, match=msg):
             tm.assert_frame_equal(result_agg, expected)
-            tm.assert_frame_equal(result_how, expected)
+    else:
+        tm.assert_frame_equal(result_agg, expected)
 
 
 @all_ts

pandas/tests/resample/test_period_index.py

@@ -732,12 +732,9 @@ def test_loffset_returns_datetimeindex(self, frame, kind, agg_arg):
         expected = DataFrame({"value": expected_means}, index=expected_index)
 
         result_agg = df.resample("2D", loffset="2H", kind=kind).agg(agg_arg)
-        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False):
-            result_how = df.resample("2D", how=agg_arg, loffset="2H", kind=kind)
         if isinstance(agg_arg, list):
             expected.columns = pd.MultiIndex.from_tuples([("value", "mean")])
         tm.assert_frame_equal(result_agg, expected)
-        tm.assert_frame_equal(result_how, expected)
 
     @pytest.mark.parametrize("freq, period_mult", [("H", 24), ("12H", 2)])
     @pytest.mark.parametrize("kind", [None, "period"])

pandas/tests/resample/test_resample_api.py

@@ -179,17 +179,57 @@ def test_downsample_but_actually_upsampling():
 
 def test_combined_up_downsampling_of_irregular():
 
-    # since we are reallydoing an operation like this
+    # since we are really doing an operation like this
     # ts2.resample('2s').mean().ffill()
     # preserve these semantics
 
     rng = pd.date_range("1/1/2012", periods=100, freq="S")
     ts = Series(np.arange(len(rng)), index=rng)
     ts2 = ts.iloc[[0, 1, 2, 3, 5, 7, 11, 15, 16, 25, 30]]
 
-    with tm.assert_produces_warning(FutureWarning, check_stacklevel=False):
-        result = ts2.resample("2s", how="mean", fill_method="ffill")
-    expected = ts2.resample("2s").mean().ffill()
+    result = ts2.resample("2s").mean().ffill()
+    expected = Series(
+        [
+            0.5,
+            2.5,
+            5.0,
+            7.0,
+            7.0,
+            11.0,
+            11.0,
+            15.0,
+            16.0,
+            16.0,
+            16.0,
+            16.0,
+            25.0,
+            25.0,
+            25.0,
+            30.0,
+        ],
+        index=pd.DatetimeIndex(
+            [
+                "2012-01-01 00:00:00",
+                "2012-01-01 00:00:02",
+                "2012-01-01 00:00:04",
+                "2012-01-01 00:00:06",
+                "2012-01-01 00:00:08",
+                "2012-01-01 00:00:10",
+                "2012-01-01 00:00:12",
+                "2012-01-01 00:00:14",
+                "2012-01-01 00:00:16",
+                "2012-01-01 00:00:18",
+                "2012-01-01 00:00:20",
+                "2012-01-01 00:00:22",
+                "2012-01-01 00:00:24",
+                "2012-01-01 00:00:26",
+                "2012-01-01 00:00:28",
+                "2012-01-01 00:00:30",
+            ],
+            dtype="datetime64[ns]",
+            freq="2S",
+        ),
+    )
     tm.assert_series_equal(result, expected)