Check Python version from inside script? Run Pythons script in v2 compatibility mode?

[Terry Reedy]

On 7/7/2017 2:30 AM, Ben S. via Python-list wrote:
> Can I somehow check from inside a Python script if the executing Python engine is major version v2 or v3?
> 
> I am thinking about a code similar to
> 
> if (os.python-majorversion<3)
>    print hello
> else
>    print (hello)

For this, just use print('hello').
Checkout 'from __future__ import print_function'
check __future__ module for spelling.
Checkout sys.version, sys.hexversion, platform module,

Some import will tell you.

try:
     import tkinter as tk
     pyversion = 3
except ImportError:
     import Tkinter as tk
     pyversion = 2

> 
> Additional question:
> Is there a way to execute a python script with v3 python engine in v2 compatibility mode?
> I am thinking about a command parameter like (python.exe is v3.*):
> 
>    python.exe -execute_as_v2 myscript.py

No.


-- 
Terry Jan Reedy