ERR/DEPR: Fix quantile error message / remove percentile_width

doc/source/whatsnew/v0.17.0.txt

@@ -654,6 +654,7 @@ Removal of prior version deprecations/changes
 
 - Remove use of some deprecated numpy comparison operations, mainly in tests. (:issue:`10569`)
 - Removal of ``na_last`` parameters from ``Series.order()`` and ``Series.sort()``, in favor of ``na_position``, xref (:issue:`5231`)
+- Remove of ``percentile_width`` from ``.describe()``, in favor of ``percentiles``. (:issue:`7088`)
 
 .. _whatsnew_0170.performance:
 
@@ -678,6 +679,7 @@ Bug Fixes
 - Bug in ``DataFrame.apply`` when function returns categorical series. (:issue:`9573`)
 - Bug in ``to_datetime`` with invalid dates and formats supplied (:issue:`10154`)
 - Bug in ``Index.drop_duplicates`` dropping name(s) (:issue:`10115`)
+- Bug in ``Series.quantile`` dropping name (:issue:`10881`)
 - Bug in ``pd.Series`` when setting a value on an empty ``Series`` whose index has a frequency. (:issue:`10193`)
 - Bug in ``pd.Series.interpolate`` with invalid ``order`` keyword values. (:issue:`10633`)
 - Bug in ``DataFrame.plot`` raises ``ValueError`` when color name is specified by multiple characters (:issue:`10387`)

pandas/core/frame.py

@@ -4684,6 +4684,7 @@ def quantile(self, q=0.5, axis=0, numeric_only=True):
         0.1  1.3   3.7
         0.5  2.5  55.0
         """
+        self._check_percentile(q)
         per = np.asarray(q) * 100
 
         if not com.is_list_like(per):
@@ -4718,7 +4719,9 @@ def f(arr, per):
 
         quantiles = [[f(vals, x) for x in per]
                      for (_, vals) in data.iteritems()]
-        result = DataFrame(quantiles, index=data._info_axis, columns=q).T
+
+        result = self._constructor(quantiles, index=data._info_axis,
+                                   columns=q).T
         if len(is_dt_col) > 0:
             result[is_dt_col] = result[is_dt_col].applymap(lib.Timestamp)
         if squeeze:

pandas/core/generic.py

@@ -2989,7 +2989,7 @@ def interpolate(self, method='linear', axis=0, limit=None, inplace=False,
             * 'nearest', 'zero', 'slinear', 'quadratic', 'cubic',
               'barycentric', 'polynomial' is passed to
               ``scipy.interpolate.interp1d``. Both 'polynomial' and 'spline'
-              require that you also specify an `order` (int), 
+              require that you also specify an `order` (int),
               e.g. df.interpolate(method='polynomial', order=4).
               These use the actual numerical values of the index.
             * 'krogh', 'piecewise_polynomial', 'spline', and 'pchip' are all
@@ -4096,11 +4096,6 @@ def abs(self):
 
         Parameters
         ----------
-        percentile_width : float, deprecated
-            The ``percentile_width`` argument will be removed in a future
-            version. Use ``percentiles`` instead.
-            width of the desired uncertainty interval, default is 50,
-            which corresponds to lower=25, upper=75
         percentiles : array-like, optional
             The percentiles to include in the output. Should all
             be in the interval [0, 1]. By default `percentiles` is
@@ -4149,36 +4144,17 @@ def abs(self):
         """
 
     @Appender(_shared_docs['describe'] % _shared_doc_kwargs)
-    def describe(self, percentile_width=None, percentiles=None, include=None, exclude=None ):
+    def describe(self, percentiles=None, include=None, exclude=None ):
         if self.ndim >= 3:
             msg = "describe is not implemented on on Panel or PanelND objects."
             raise NotImplementedError(msg)
 
-        if percentile_width is not None and percentiles is not None:
-            msg = "Cannot specify both 'percentile_width' and 'percentiles.'"
-            raise ValueError(msg)
         if percentiles is not None:
             # get them all to be in [0, 1]
+            self._check_percentile(percentiles)
             percentiles = np.asarray(percentiles)
-            if (percentiles > 1).any():
-                percentiles = percentiles / 100.0
-                msg = ("percentiles should all be in the interval [0, 1]. "
-                       "Try {0} instead.")
-                raise ValueError(msg.format(list(percentiles)))
         else:
-            # only warn if they change the default
-            if percentile_width is not None:
-                do_warn = True
-            else:
-                do_warn = False
-            percentile_width = percentile_width or 50
-            lb = .5 * (1. - percentile_width / 100.)
-            ub = 1. - lb
-            percentiles = np.array([lb, 0.5, ub])
-            if do_warn:
-                msg = ("The `percentile_width` keyword is deprecated. "
-                       "Use percentiles={0} instead".format(list(percentiles)))
-                warnings.warn(msg, FutureWarning)
+            percentiles = np.array([0.25, 0.5, 0.75])
 
         # median should always be included
         if (percentiles != 0.5).all():  # median isn't included
@@ -4256,6 +4232,20 @@ def describe_1d(data, percentiles):
         d = pd.concat(ldesc, join_axes=pd.Index([names]), axis=1)
         return d
 
+    def _check_percentile(self, q):
+        """ Validate percentiles. Used by describe and quantile """
+
+        msg = ("percentiles should all be in the interval [0, 1]. "
+               "Try {0} instead.")
+        q = np.asarray(q)
+        if q.ndim == 0:
+            if not 0 <= q <= 1:
+                raise ValueError(msg.format(q / 100.0))
+        else:
+            if not all(0 <= qs <= 1 for qs in q):
+                raise ValueError(msg.format(q / 100.0))
+        return q
+
     _shared_docs['pct_change'] = """
         Percent change over given number of periods.
 

pandas/core/series.py

@@ -1266,11 +1266,12 @@ def quantile(self, q=0.5):
         dtype: float64
         """
         valid = self.dropna()
+        self._check_percentile(q)
 
         def multi(values, qs):
             if com.is_list_like(qs):
-                return Series([_quantile(values, x*100)
-                               for x in qs], index=qs)
+                values = [_quantile(values, x*100) for x in qs]
+                return self._constructor(values, index=qs, name=self.name)
             else:
                 return _quantile(values, qs*100)
 

pandas/tests/test_frame.py

@@ -12837,6 +12837,12 @@ def test_quantile_datetime(self):
                              index=[0.5], columns=[0, 1])
         assert_frame_equal(result, expected)
 
+    def test_quantile_invalid(self):
+        msg = 'percentiles should all be in the interval \\[0, 1\\]'
+        for invalid in [-1, 2, [0.5, -1], [0.5, 2]]:
+            with tm.assertRaisesRegexp(ValueError, msg):
+                self.tsframe.quantile(invalid)
+
     def test_cumsum(self):
         self.tsframe.ix[5:10, 0] = nan
         self.tsframe.ix[10:15, 1] = nan

pandas/tests/test_generic.py

@@ -909,17 +909,6 @@ def test_describe(self):
         _ = self.series.describe()
         _ = self.ts.describe()
 
-    def test_describe_percentiles(self):
-        with tm.assert_produces_warning(FutureWarning):
-            desc = self.series.describe(percentile_width=50)
-        assert '75%' in desc.index
-        assert '25%' in desc.index
-
-        with tm.assert_produces_warning(FutureWarning):
-            desc = self.series.describe(percentile_width=95)
-        assert '97.5%' in desc.index
-        assert '2.5%' in desc.index
-
     def test_describe_objects(self):
         s = Series(['a', 'b', 'b', np.nan, np.nan, np.nan, 'c', 'd', 'a', 'a'])
         result = s.describe()
@@ -1181,27 +1170,19 @@ def test_describe(self):
         desc = tm.makeMixedDataFrame().describe()
         desc = tm.makeTimeDataFrame().describe()
 
-    def test_describe_percentiles(self):
-        with tm.assert_produces_warning(FutureWarning):
-            desc = tm.makeDataFrame().describe(percentile_width=50)
-        assert '75%' in desc.index
-        assert '25%' in desc.index
-
-        with tm.assert_produces_warning(FutureWarning):
-            desc = tm.makeDataFrame().describe(percentile_width=95)
-        assert '97.5%' in desc.index
-        assert '2.5%' in desc.index
-
-    def test_describe_quantiles_both(self):
-        with tm.assertRaises(ValueError):
-            tm.makeDataFrame().describe(percentile_width=50,
-                                        percentiles=[25, 75])
-
     def test_describe_percentiles_percent_or_raw(self):
+        msg = 'percentiles should all be in the interval \\[0, 1\\]'
+
         df = tm.makeDataFrame()
-        with tm.assertRaises(ValueError):
+        with tm.assertRaisesRegexp(ValueError, msg):
             df.describe(percentiles=[10, 50, 100])
 
+        with tm.assertRaisesRegexp(ValueError, msg):
+            df.describe(percentiles=[2])
+
+        with tm.assertRaisesRegexp(ValueError, msg):
+            df.describe(percentiles=[-2])
+
     def test_describe_percentiles_equivalence(self):
         df = tm.makeDataFrame()
         d1 = df.describe()
@@ -1213,16 +1194,29 @@ def test_describe_percentiles_insert_median(self):
         d1 = df.describe(percentiles=[.25, .75])
         d2 = df.describe(percentiles=[.25, .5, .75])
         assert_frame_equal(d1, d2)
+        self.assertTrue('25%' in d1.index)
+        self.assertTrue('75%' in d2.index)
 
         # none above
         d1 = df.describe(percentiles=[.25, .45])
         d2 = df.describe(percentiles=[.25, .45, .5])
         assert_frame_equal(d1, d2)
+        self.assertTrue('25%' in d1.index)
+        self.assertTrue('45%' in d2.index)
 
         # none below
         d1 = df.describe(percentiles=[.75, 1])
         d2 = df.describe(percentiles=[.5, .75, 1])
         assert_frame_equal(d1, d2)
+        self.assertTrue('75%' in d1.index)
+        self.assertTrue('100%' in d2.index)
+
+        # edge
+        d1 = df.describe(percentiles=[0, 1])
+        d2 = df.describe(percentiles=[0, .5, 1])
+        assert_frame_equal(d1, d2)
+        self.assertTrue('0%' in d1.index)
+        self.assertTrue('100%' in d2.index)
 
     def test_describe_no_numeric(self):
         df = DataFrame({'A': ['foo', 'foo', 'bar'] * 8,

pandas/tests/test_series.py

@@ -2854,21 +2854,32 @@ def test_quantile(self):
         result = Series([np.timedelta64('NaT')]).sum()
         self.assertTrue(result is pd.NaT)
 
+        msg = 'percentiles should all be in the interval \\[0, 1\\]'
+        for invalid in [-1, 2, [0.5, -1], [0.5, 2]]:
+            with tm.assertRaisesRegexp(ValueError, msg):
+                self.ts.quantile(invalid)
+
     def test_quantile_multi(self):
         from numpy import percentile
 
         qs = [.1, .9]
         result = self.ts.quantile(qs)
         expected = pd.Series([percentile(self.ts.valid(), 10),
                               percentile(self.ts.valid(), 90)],
-                             index=qs)
+                             index=qs, name=self.ts.name)
         assert_series_equal(result, expected)
 
         dts = self.ts.index.to_series()
+        dts.name = 'xxx'
         result = dts.quantile((.2, .2))
-        assert_series_equal(result, Series([Timestamp('2000-01-10 19:12:00'),
-                                            Timestamp('2000-01-10 19:12:00')],
-                                           index=[.2, .2]))
+        expected = Series([Timestamp('2000-01-10 19:12:00'),
+                           Timestamp('2000-01-10 19:12:00')],
+                          index=[.2, .2], name='xxx')
+        assert_series_equal(result, expected)
+
+        result = self.ts.quantile([])
+        expected = pd.Series([], name=self.ts.name)
+        assert_series_equal(result, expected)
 
     def test_append(self):
         appendedSeries = self.series.append(self.objSeries)