I am using a screen on my server. When I ask which python inside the screen I see it is using the default /opt/anaconda2/bin/python version which is on my server, but outside the screen when I ask which python I get ~/anaconda2/bin/python. I want to use the same python inside the screen but I don't know how can I set it. Both path are available in $PATH
You could do either one of the following:

Use a virtual environment (install virtualenv). You can specify
the version of Python you want to use when creating the virtual
environment with -p /opt/anaconda2/bin/python.
Use an alias:
alias python=/opt/anaconda2/bin/python.
Force screen session to use specific version of python