ENH: error message with malformed CSV file #1105

Author: Chang She

pandas/io/parsers.py

@@ -710,8 +710,9 @@ def get_chunk(self, rows=None):
         #                % (idx_str, self.index_col, str(dups)))
         #     raise Exception(err_msg)
 
-        if len(self.columns) != len(zipped_content):
-            raise Exception('wrong number of columns')
+        col_len, zip_len = len(self.columns), len(zipped_content)
+        if col_len != zip_len:
+            raise Exception('Expecting %d columns, got %d' % (col_len, zip_len))
 
         data = dict((k, v) for k, v in izip(self.columns, zipped_content))
 

pandas/io/tests/test_parsers.py

@@ -92,6 +92,13 @@ def test_comment_fwf(self):
                       comment='#')
         assert_almost_equal(df.values, expected)
 
+    def test_malformed(self):
+        data = """A,B,C
+1,2,3,4,5
+"""
+        self.assertRaises(Exception, 'read_table', StringIO(data),
+                          names=['A','B','C'], index_col=0)
+
     def test_custom_na_values(self):
         data = """A,B,C
 ignore,this,row