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BUG: (GH3611) Fix read_csv to correctly encode identical na_values #3615

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Merged
merged 1 commit into from
May 16, 2013
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BUG: (GH3611) Fix read_csv to correctly encode identical na_values #3615

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3 changes: 3 additions & 0 deletions RELEASE.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -118,6 +118,8 @@ pandas 0.11.1
- Fix modulo and integer division on Series,DataFrames to act similary to ``float`` dtypes to return
``np.nan`` or ``np.inf`` as appropriate (GH3590_)
- Fix incorrect dtype on groupby with ``as_index=False`` (GH3610_)
- Fix ``read_csv`` to correctly encode identical na_values, e.g. ``na_values=[-999.0,-999]``
was failing (GH3611_)

.. _GH3164: https://github.com/pydata/pandas/issues/3164
.. _GH2786: https://github.com/pydata/pandas/issues/2786
Expand Down Expand Up @@ -166,6 +168,7 @@ pandas 0.11.1
.. _GH3610: https://github.com/pydata/pandas/issues/3610
.. _GH3596: https://github.com/pydata/pandas/issues/3596
.. _GH3435: https://github.com/pydata/pandas/issues/3435
.. _GH3611: https://github.com/pydata/pandas/issues/3611


pandas 0.11.0
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6 changes: 4 additions & 2 deletions pandas/io/parsers.py
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Expand Up @@ -1712,12 +1712,14 @@ def _clean_na_values(na_values, keep_default_na=True):
else:
if not com.is_list_like(na_values):
na_values = [na_values]
na_values = set(list(na_values))
na_values = set(_stringify_na_values(na_values))
if keep_default_na:
na_values = na_values | _NA_VALUES

return na_values

def _stringify_na_values(na_values):
return [ str(x) for x in na_values ]

def _clean_index_names(columns, index_col):
if not _is_index_col(index_col):
Expand Down Expand Up @@ -1768,7 +1770,7 @@ def _get_empty_meta(columns, index_col, index_names):
def _get_na_values(col, na_values):
if isinstance(na_values, dict):
if col in na_values:
return set(list(na_values[col]))
return set(_stringify_na_values(list(na_values[col])))
else:
return _NA_VALUES
else:
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11 changes: 11 additions & 0 deletions pandas/io/tests/test_parsers.py
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Expand Up @@ -498,6 +498,17 @@ def test_quoting(self):
df = self.read_table(StringIO(good_line_small), sep='\t')
self.assert_(len(df) == 3)

def test_non_string_na_values(self):
# GH3611, na_values that are not a string are an issue
with ensure_clean('__non_string_na_values__.csv') as path:
df = DataFrame({'A' : [-999, 2, 3], 'B' : [1.2, -999, 4.5]})
df.to_csv(path, sep=' ', index=False)
result1 = read_csv(path, sep= ' ', header=0, na_values=['-999.0','-999'])
result2 = read_csv(path, sep= ' ', header=0, na_values=[-999,-999.0])
result3 = read_csv(path, sep= ' ', header=0, na_values=[-999.0,-999])
tm.assert_frame_equal(result1,result2)
tm.assert_frame_equal(result2,result3)

def test_custom_na_values(self):
data = """A,B,C
ignore,this,row
Expand Down