Merge pull request #8218 from jreback/squeeze

BUG: Bug in read_csv where squeeze=True would return a view (GH8217)

Author: jreback

doc/source/v0.15.0.txt

@@ -480,7 +480,6 @@ Enhancements
 
 
 
-- Bug in ``DataFrame.groupby`` where ``Grouper`` does not recognize level when frequency is specified (:issue:`7885`)
 
 
 - Bug in ``get`` where an ``IndexError`` would not cause the default value to be returned (:issue:`7725`)
@@ -539,7 +538,9 @@ There are no experimental changes in 0.15.0
 Bug Fixes
 ~~~~~~~~~
 
+- Bug in ``read_csv`` where ``squeeze=True`` would return a view (:issue:`8217`)
 - Bug in checking of table name in ``read_sql`` in certain cases (:issue:`7826`).
+- Bug in ``DataFrame.groupby`` where ``Grouper`` does not recognize level when frequency is specified (:issue:`7885`)
 - Bug in multiindexes dtypes getting mixed up when DataFrame is saved to SQL table (:issue:`8021`)
 - Bug in Series 0-division with a float and integer operand dtypes  (:issue:`7785`)
 - Bug in ``Series.astype("unicode")`` not calling ``unicode`` on the values correctly (:issue:`7758`)

pandas/io/parsers.py

@@ -703,7 +703,7 @@ def read(self, nrows=None):
         df = DataFrame(col_dict, columns=columns, index=index)
 
         if self.squeeze and len(df.columns) == 1:
-            return df[df.columns[0]]
+            return df[df.columns[0]].copy()
         return df
 
     def _create_index(self, ret):

pandas/io/tests/test_parsers.py

@@ -263,6 +263,15 @@ def test_squeeze(self):
         tm.assert_isinstance(result, Series)
         tm.assert_series_equal(result, expected)
 
+    def test_squeeze_no_view(self):
+
+        # GH 8217
+        # series should not be a view
+
+        data = """time,data\n0,10\n1,11\n2,12\n4,14\n5,15\n3,13"""
+        result = self.read_csv(StringIO(data), index_col='time', squeeze=True)
+        self.assertFalse(result._is_view)
+
     def test_inf_parsing(self):
         data = """\
 ,A