How do I detect the Python version at runtime

Question

I have a Python file which might have to support Python versions  lt  3 x and    3 x  Is there a way to introspect the Python runtime to know the version which it is running  for example  2 6 or 3 2 x

User · Answer

The best solution depends on how much code is incompatible. If there are a lot of places you need to support Python 2 and 3, six is the compatibility module. six.PY2 and six.PY3 are two booleans if you want to check the version.

However, a better solution than using a lot of if statements is to use six compatibility functions if possible. Hypothetically, if Python 3000 has a new syntax for next, someone could update six so your old code would still work.

import six

#OK
if six.PY2:
  x = it.next() # Python 2 syntax
else:
  x = next(it) # Python 3 syntax

#Better
x = six.next(it)

http://pythonhosted.org/six/

Cheers

User · Answer

Version check example below  Note that I do not stop the execution  this snippet just  - do nothing if exact version matches - write INFO if revision  last number  is different - write WARN if any of major minor are different  import sys import warnings  def checkVersion          Checking Python version      expect major   2     expect minor   7     expect rev   14     if sys version info  3      expect major  expect minor  expect rev           print  INFO  Script developed and tested with Python     str expect major          str expect minor          str expect rev           current version   str sys version info 0       str sys version info 1       str sys version info 2           if sys version info  2      expect major  expect minor               warnings warn  Current Python version was unexpected  Python     current version          else              print        Current version is different  Python     current version

User · Answer

To make the scripts compatible with Python2 and 3 i use    from sys import version info if version info 0   lt  3      from   future   import print function

User · Answer

Just in case you want to see all of the gory details in human readable form  you can use   import platform   print platform sys version     Output for my system   3 6 5  Anaconda  Inc    default  Apr 29 2018  16 14 56    GCC 7 2 0    Something very detailed but machine parsable would be to get the version info object from platform sys  instead  and then use its properties to take a predetermined course of action  For example   import platform   print platform sys version info    Output on my system   sys version info major 3  minor 6  micro 5  releaselevel  final   serial 0

User · Answer

Since all you are interested in is whether you have Python 2 or 3  a bit hackish but definitely the simplest and 100  working way of doing that would be as follows   python python version major   3 2 2  The only drawback of this is that when there is Python 4  it will probably still give you 3

User · Answer

Per sys hexversion and API and ABI Versioning   import sys if sys hexversion  gt   0x3000000      print  Python 3 x hexversion  s is in use     hex sys hexversion

User · Answer

Try this code  this should work   import platform print platform python version

User · Answer

Sure  take a look at sys version and sys version info   For example  to check that you are running Python 3 x  use  import sys if sys version info 0   lt  3      raise Exception  Must be using Python 3     Here  sys version info 0  is the major version number  sys version info 1  would give you the minor version number   In Python 2 7 and later  the components of sys version info can also be accessed by name  so the major version number is sys version info major   See also How can I check for Python version in a program that uses new language features

User · Answer

Here s some code I use with sys version info to check the Python installation   def check installation rv       current version   sys version info     if current version 0     rv 0  and current version 1   gt   rv 1           pass     else          sys stderr write     s  - Error  Your Python interpreter must be  d  d or greater  within major version  d  n     sys argv 0   rv 0   rv 1   rv 0             sys exit -1      return 0         Calling the  check installation  function checks if Python is  gt   2 7 and  lt  3 required version    2 7  check installation required version

[python] How do I detect the Python version at runtime?

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