BUG: correct inf/-inf handling in read_csv. close #2041

Author: wesm

RELEASE.rst

@@ -37,6 +37,7 @@ pandas 0.9.1
 
 **Bug fixes**
 
+  - Handle inf/-inf correctly in read_* parser functions (#2041)
   - Fix matplotlib unicode interaction bug
   - Make WLS r-squared match statsmodels 0.5.0 fixed value
   - Fix zero-trimming DataFrame formatting bug

pandas/io/tests/test_parsers.py

@@ -196,6 +196,15 @@ def test_squeeze(self):
         self.assert_(isinstance(result, Series))
         assert_series_equal(result, expected)
 
+
+    def test_inf_parsing(self):
+        data = """\
+,A
+a,inf
+b,-inf"""
+        df = read_csv(StringIO(data), index_col=0)
+        self.assertTrue(np.isinf(np.abs(df['A'])).all())
+
     def test_multiple_date_col(self):
         # Can use multiple date parsers
         data = """\

pandas/src/inference.pyx

@@ -357,7 +357,7 @@ def maybe_convert_numeric(ndarray[object] values, set na_values,
             fval = util.floatify(val)
             floats[i] = fval
             if not seen_float:
-                if '.' in val:
+                if '.' in val or fval == INF or fval == NEGINF:
                     seen_float = 1
                 else:
                     ints[i] = <int64_t> fval