Windows Command Line Python Change Version

Question

New to Python and programming in general. I want to "install" a module from the command line for v 2.6, but it looks like my default Python is 2.5. (python --version returns 2.5.4)

How can I run my python setup.py build/install on 2.6 instead?

Many thanks in advance,

Brock

• user202729: Does this answer your question? How to run multiple Python versions on Windows

Answer 1

You can use explicit paths:

c:\python26\python setup.py install
c:\python25\python setup.py install

Recent versions of Python install PyLauncher. It is installed in the path so no need to add an explicit Python to the path, and it allows easy switching between multiple Python versions.

Examples:

py -3 setup.py # run latest Python 3
py -2 setup.py # run latest Python 2
py -3.3
py -2.7-32 # use 32-bit version
py # run default version

The default version can be specified in the environment variable PY_PYTHON, e.g. PY_PYTHON=3 (latest Python 3).

Answer 2

It depends on your operating system. If you have python 2.6 installed, you need to change your environment path to point to the 2.6 executable rather than the 2.5 executable. Do a Google search for changing your PATH variable on your operating system.

• Btibert3: Just for reference: this was a great help people.cis.ksu.edu/~schmidt/301f09/setpath.html

Answer 3

If you're on Windows and you just need to run a different version of Python temporarily or, as was the case for me, a third party program needs to run a different version of Python, then modify your path at the command prompt:

> python --version
> set PATH=<path-to-desired-python-version>;%PATH%
> python --version

For me it was:

> python --version
Python 3.4.2
> set PATH=C:\tools\python2\;%PATH%
> python --version
Python 2.7.9
> npm install...
(success)

This allowed the third party program to install successfully. The PATH modification only affects programs running in the same command prompt session and only lasts as long as the command prompt session..

Answer 4

They are a couple of ways you can do this 1) python virtual environment 2) pylauncher 3) Changing your windows path variable, tedious to say the least

All three outlined in this video https://www.youtube.com/watch?v=ynDlb0n27cw

Answer 5

It sounds like you are on windows. If so, run this with the python you want, to set that python as the windows one. (not my code)

import sys
from _winreg import *
# tweak as necessary
version = sys.version[:3]
installpath = sys.prefix
regpath = "SOFTWARE\\Python\\Pythoncore\\%s\\" % (version)
installkey = "InstallPath"
pythonkey = "PythonPath"
pythonpath = "%s;%s\\Lib\\;%s\\DLLs\\" % (
 installpath, installpath, installpath
)
def RegisterPy():
 try:
 reg = OpenKey(HKEY_LOCAL_MACHINE, regpath)
 except EnvironmentError:
 try:
 reg = CreateKey(HKEY_LOCAL_MACHINE, regpath)
 except Exception, e:
 print "*** Unable to register: %s" % e
 return
 SetValue(reg, installkey, REG_SZ, installpath)
 SetValue(reg, pythonkey, REG_SZ, pythonpath)
 CloseKey(reg)
 print "--- Python %s at %s is now registered!" % (version, installpath)
if __name__ == "__main__":
 RegisterPy()