Backporting Python 3 open encoding utf-8 to Python 2

Question

I have a Python codebase  built for Python 3  which uses Python 3 style open   with encoding parameter   https   github com miohtama vvv blob master vvv textlineplugin py L47      with open fname   rt   encoding  utf-8   as f    Now I d like to backport this code to Python 2 x  so that I would have a codebase which works with Python 2 and Python 3   What s the recommended strategy to work around open   differences and lack of encoding parameter   Could I have a Python 3 open   style file handler which streams bytestrings  so it would act like Python 2 open

User · Answer

I think   from io import open   should do

User · Answer

Here s one way   with open  filename txt    rb   as f      contents   f read   decode  UTF-8

User · Answer

1  To get an encoding parameter in Python 2  If you only need to support Python 2 6 and 2 7 you can use io open instead of open  io is the new io subsystem for Python 3  and it exists in Python 2 6 ans 2 7 as well  Please be aware that in Python 2 6  as well as 3 0  it s implemented purely in python and very slow  so if you need speed in reading files  it s not a good option  If you need speed  and you need to support Python 2 6 or earlier  you can use codecs open instead  It also has an encoding parameter  and is quite similar to io open except it handles line-endings differently  2  To get a Python 3 open   style file handler which streams bytestrings  open filename   rb    Note the  b   meaning  binary

User · Answer

If you are using six  you can try this  by which utilizing the latest Python 3 API and can run in both Python 2 3   import six  if six PY2        FileNotFoundError is only available since Python 3 3     FileNotFoundError   IOError     from io import open  fname    index rst  try      with open fname   rt   encoding  utf-8   as f          pass           do something with f     except FileNotFoundError      print  Oops      And  Python 2 support abandon is just deleting everything related to six

User · Answer

This may do the trick   import sys if sys version info 0   gt  2        py3k     pass else        py2     import codecs     import warnings     def open file  mode  r   buffering -1  encoding None               errors None  newline None  closefd True  opener None           if newline is not None              warnings warn  newline is not supported in py2           if not closefd              warnings warn  closefd is not supported in py2           if opener is not None              warnings warn  opener is not supported in py2           return codecs open filename file  mode mode  encoding encoding                      errors errors  buffering buffering    Then you can keep you code in the python3 way   Note that some APIs like newline  closefd  opener do not work

User · Answer

Not a general answer  but may be useful for the specific case where you are happy with the default python 2 encoding  but want to specify utf-8 for python 3  if sys version info major  gt  2      do open   lambda filename  open filename  encoding  utf-8   else      do open   lambda filename  open filename   with do open filename  as file      pass

[python] Backporting Python 3 open(encoding="utf-8") to Python 2

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