Tjyylli

I have Python 3.6 installed but need Python 2.7 for a project. I cannot install packages for Python 2.7 though. Let's use numpy as an example:

C:Python27python.exe -m pip install numpy

will tell me that requirement is already met in 3.6.

C:Python27Scriptspip2.7.exe install numpy

will tell me that requirement is already met in 3.6.

When I try to import numpy it will give me an error.

I tried adding Python 2.7 to my path above Python 3.6 and I still get the error.

Please help, this has been extraordinarily frustrating.

Thank you.

For reference, running C:Python27python.exe -m pip install numpy and python -m install numpy (for Python 3.6, outside C:Python27) yielded no errors for me.

Troubleshooting

You may wish to consider one or more of the following.

Uninstall numpy

Uninstall numpy (or any requirements that are already met, assuming you do not need them) in Python 3.6 (ex. python -m pip uninstall numpy) and then install e.g. numpy again in Python 2.7.

Use A Virtual Environment

Assuming that your Python 2.7 installation will allow it:

• Run e.g. C:Python27python.exe -m pip install virtualenv to download the virtualenv virtual environment package.




• Run C:Python27python.exe -m virtualenv C:pathtovirtualenv to create an isolated 2.7 environment in which you can install numpy (or any other necessary packages) for your project.




• Note that you will need to "activate" (and perhaps "deactivate") this environment from the command line with the activate.bat (or deactivate.bat) batch file(s) located in e.g. C:pathtovirtualenvScripts.

Check pip Paths

Running e.g. C:Python27python.exe -m pip list and ex. python -m pip list (again, outside C:Python27) should output different lists of installed packages (one for 2.7 and one for 3.6, respectively).

If they do not, you may wish look for any duplicate references to e.g. C:PythonVersionScripts (where pip.exe resides) in your PATHPath (UserSystem) variables and remove them. In short, you should only have a single reference to e.g. C:Python36Scripts (i.e. no C:Python27Scripts).

Reinstall Python 2.7 and Python 3.6

• Completely uninstall Python 2.7 and Python 3.6, taking note of any packages you may wish to reinstall later.




• Install Python 2.7. Do not choose any option to add Python 2.7 to your path variable(s).




• Install Python 3.6. Add it to your path variable(s). You do not need to select the option to add pip to your path variables if you are using e.g. python -m pip (this is only necessary if you want to use the pip installation for Python 3.6 directly as pip [options] from the command line)