Debugging: use logging rather than print

Author: dhimmel

pandas/io/formats/csvs.py

@@ -134,10 +134,12 @@ def save(self):
             encoding = self.encoding
 
         # GH 21227 internal compression is not used when file-like passed.
-        print('debug_3', self.compression)
-        print('debug_4', self.path_or_buf)
-        print('debug_5', hasattr(self.path_or_buf, 'write'))
+        import logging
+        logging.warning('debug_3: {}'.format(self.compression))
+        logging.warning('debug_4: {}'.format(self.path_or_buf))
+        logging.warning('debug_5: {}'.format(hasattr(self.path_or_buf, 'write')))
         if self.compression and hasattr(self.path_or_buf, 'write'):
+            logging.warning('debug_6: in loop, should RuntimeWarn')
             msg = ("compression has no effect when passing file-like "
                    "object as input.")
             warnings.warn(msg, RuntimeWarning, stacklevel=2)

pandas/tests/test_common.py

@@ -257,10 +257,11 @@ def test_compression_warning(compression_only):
                           [12.32112, 123123.2, 321321.2]],
                    columns=['X', 'Y', 'Z'])
     with tm.ensure_clean() as filename:
-        print('debug_1', compression_only)
+        import logging
+        logging.warning('debug_1: {}'.format(compression_only))
         f, _handles = _get_handle(filename, 'w', compression=compression_only)
         with tm.assert_produces_warning(RuntimeWarning,
                                         check_stacklevel=False):
             with f:
-                print('debug_2', compression_only)
+                logging.warning('debug_2: {}'.format(compression_only))
                 df.to_csv(f, compression=compression_only)