python virtual environments

With python 2.x use virtualenv

$ virtualenv env

This will make a virtual environment with current python version. If current python is python 2.x but make a virtual environment with python3 then specify the python3 binary with -p option.

$ virtualenv -p python3 env

With python 3.x use lightweight virtual environment.

$ python3 -m venv env

If installed the python 3.x with Homebrew, the binary name of the python 3.x would be python3.