PERF: fix series slice indexing performance

Author: immerrr

doc/source/release.rst

@@ -79,7 +79,7 @@ Improvements to existing features
 - ``plot(legend='reverse')`` will now reverse the order of legend labels for most plot kinds.
   (:issue:`6014`)
 - Allow multi-index slicers (:issue:`6134`, :issue:`4036`, :issue:`3057`, :issue:`2598`, :issue:`5641`)
-- improve performance of slice indexing on Series with string keys (:issue:`6341`)
+- improve performance of slice indexing on Series with string keys (:issue:`6341`, :issue:`6372`)
 - implement joining a single-level indexed DataFrame on a matching column of a multi-indexed DataFrame (:issue:`3662`)
 - Performance improvement in indexing into a multi-indexed Series (:issue:`5567`)
 - Testing statements updated to use specialized asserts (:issue: `6175`)

doc/source/v0.14.0.txt

@@ -153,7 +153,7 @@ Enhancements
   and parse accordingly. (:issue:`6223`)
 - ``plot(legend='reverse')`` will now reverse the order of legend labels for
   most plot kinds. (:issue:`6014`)
-- improve performance of slice indexing on Series with string keys (:issue:`6341`)
+- improve performance of slice indexing on Series with string keys (:issue:`6341`, :issue:`6372`)
 - Hexagonal bin plots from ``DataFrame.plot`` with ``kind='hexbin'`` (:issue:`5478`)
 - Joining a singly-indexed DataFrame with a multi-indexed DataFrame (:issue:`3662`)
 

pandas/core/series.py

@@ -463,8 +463,7 @@ def _slice(self, slobj, axis=0, raise_on_error=False, typ=None):
         if raise_on_error:
             _check_slice_bounds(slobj, self.values)
         slobj = self.index._convert_slice_indexer(slobj, typ=typ or 'getitem')
-        return self._constructor(self.values[slobj],
-                                 index=self.index[slobj]).__finalize__(self)
+        return self._get_values(slobj)
 
     def __getitem__(self, key):
         try:
@@ -679,23 +678,6 @@ def _set_values(self, key, value):
     # help out SparseSeries
     _get_val_at = ndarray.__getitem__
 
-    def __getslice__(self, i, j):
-        if i < 0:
-            i = 0
-        if j < 0:
-            j = 0
-        slobj = slice(i, j)
-        return self._slice(slobj)
-
-    def __setslice__(self, i, j, value):
-        """Set slice equal to given value(s)"""
-        if i < 0:
-            i = 0
-        if j < 0:
-            j = 0
-        slobj = slice(i, j)
-        return self.__setitem__(slobj, value)
-
     def repeat(self, reps):
         """
         See ndarray.repeat

vb_suite/indexing.py

@@ -34,8 +34,17 @@
 index = tm.makeStringIndex(1000000)
 s = Series(np.random.rand(1000000), index=index)
 """
-series_getitem_slice = Benchmark("s[:800000]", setup,
-                                 name="series_getitem_slice")
+series_getitem_pos_slice = Benchmark("s[:800000]", setup,
+                                     name="series_getitem_pos_slice")
+
+
+setup = common_setup + """
+index = tm.makeStringIndex(1000000)
+s = Series(np.random.rand(1000000), index=index)
+lbl = s.index[800000]
+"""
+series_getitem_label_slice = Benchmark("s[:lbl]", setup,
+                                       name="series_getitem_label_slice")
 
 
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