BUG: open file in Python 3 with given encoding

Author: wesm

pandas/core/frame.py

@@ -932,7 +932,10 @@ def to_csv(self, path_or_buf, sep=",", na_rep='', cols=None,
             f = path_or_buf
             close = False
         else:
-            f = open(path_or_buf, mode)
+            if py3compat.PY3:  # pragma: no cover
+                f = open(path_or_buf, mode, encoding=encoding)
+            else:
+                f = open(path_or_buf, mode)
             close = True
 
         try: