BUG: CSV parser fails with single line, no separator pandas-dev#1553

Author: Chang She

pandas/io/parsers.py

@@ -576,7 +576,10 @@ def _infer_columns(self):
                 counts[col] = cur_count + 1
             self._clear_buffer()
         else:
-            line = self._next_line()
+            if len(self.buf) > 0:
+                line = self.buf[0]
+            else:
+                line = self._next_line()
 
             ncols = len(line)
             if not names:

pandas/io/tests/test_parsers.py

@@ -252,6 +252,10 @@ def func(*date_cols):
         d = datetime(1999, 1, 27, 19, 0)
         self.assert_(df.index[0] == d)
 
+    def test_single_line(self):
+        df = read_csv(StringIO('1,2'), names=['a', 'b'], sep=None)
+        assert_frame_equal(DataFrame({'a': [1], 'b': [2]}), df)
+
     def test_multiple_date_cols_with_header(self):
         data = """\
 ID,date,NominalTime,ActualTime,TDew,TAir,Windspeed,Precip,WindDir