Change py's python version for current cmd instance

pyv.bat

:: changes python versoin invoked by 'py' for current cmd instance
:: https://docs.python.org/using/windows.html#customizing-default-python-versions

:: my set up:
::	installed python 3 and added it to environment variables
::	installed python 2 to another folder without adding it
::	added this script to my environment variables
:: now I use python 3 by default, and when I need to use 2 I type 'pyv' (you can change the name)

:: usage:
::	if an argument was given, version = argument
::		example: 'pyv 2.6' => 'py' will run python 2.6 if installed
::	else, toggle between python 2/default python
::		example: 'pyv' => 'py will run python 2, 'pyv' again will undo that

@echo off

if not "%~1"=="" (
	set PY_PYTHON=%1
	echo py is version %1 for this instance
) else (
	if not "%PY_PYTHON%"=="2" (
		set PY_PYTHON=2
		echo py is version 2 for this instance
	) else (
		set PY_PYTHON=""
		echo py is the default version for this instance
	)
)