BUG: in maybe_convert_numeric, if you've seen an 'inf', you've seen a float

Author: aflaxman

pandas/src/inference.pyx

@@ -359,6 +359,8 @@ def maybe_convert_numeric(ndarray[object] values, set na_values,
             if not seen_float:
                 if '.' in val:
                     seen_float = 1
+                elif 'inf' in val:  # special case to handle +/-inf
+                    seen_float = 1
                 else:
                     ints[i] = <int64_t> fval
 

pandas/tests/test_tseries.py

@@ -290,6 +290,11 @@ def test_convert_objects():
     result = lib.maybe_convert_objects(arr)
     assert(result.dtype == np.object_)
 
+def test_convert_infs():
+    arr = np.array(['inf', 'inf', 'inf'], dtype='O')
+    result = lib.maybe_convert_numeric(arr, set(), False)
+    assert(result.dtype == np.float64)
+
 def test_convert_objects_ints():
     # test that we can detect many kinds of integers
     dtypes = ['i1', 'i2', 'i4', 'i8', 'u1', 'u2', 'u4', 'u8']