BUG: Bug in popping from a Series (GH6600)

Author: jreback

doc/source/release.rst

@@ -226,7 +226,7 @@ Bug Fixes
 - Bug in ``.xs`` with a ``nan`` in level when dropped (:issue:`6574`)
 - Bug in fillna with method = 'bfill/ffill' and ``datetime64[ns]`` dtype (:issue:`6587`)
 - Bug in sql writing with mixed dtypes possibly leading to data loss (:issue:`6509`)
-
+- Bug in popping from a Series (:issue:`6600`)
 
 pandas 0.13.1
 -------------

pandas/core/internals.py

@@ -3731,11 +3731,21 @@ def reindex_axis0_with_method(self, new_axis, indexer=None, method=None,
     def _delete_from_block(self, i, item):
         super(SingleBlockManager, self)._delete_from_block(i, item)
 
-        # reset our state
-        self._block = (
-            self.blocks[0] if len(self.blocks) else
-            make_block(np.array([], dtype=self._block.dtype), [], [])
-        )
+        # possibly need to merge split blocks
+        if len(self.blocks) > 1:
+            new_items = Index(list(itertools.chain(*[ b.items for b in self.blocks ])))
+            block = make_block(np.concatenate([ b.values for b in self.blocks ]),
+                               new_items,
+                               new_items,
+                               dtype=self._block.dtype)
+
+        elif len(self.blocks):
+            block = self.blocks[0]
+        else:
+            block = make_block(np.array([], dtype=self._block.dtype), [], [])
+
+        self.blocks = [block]
+        self._block = block
         self._values = self._block.values
 
     def get_slice(self, slobj):

pandas/tests/test_series.py

@@ -710,6 +710,21 @@ def test_setindex(self):
     def test_array_finalize(self):
         pass
 
+    def test_pop(self):
+        # GH 6600
+        df = DataFrame({
+            'A': 0,
+            'B': np.arange(5,dtype='int64'),
+            'C': 0,
+            })
+        k = df.iloc[4]
+
+        result = k.pop('B')
+        self.assertEqual(result, 4)
+
+        expected = Series([0,0],index=['A','C'])
+        assert_series_equal(k, expected)
+
     def test_not_hashable(self):
         s_empty = Series()
         s = Series([1])