Assuming that you have installed python3 or any desired version of Python (2.6, 2.7, 3.5, 3.6), Now while creating the virtual environment directly pass the python executable path. Hence here are few valid example

$ virtualenv new_p2_env # Creates a new default python environment (usually python 2)$ virtualenv -p python3 new_p3_env # Creates a new default python3 (python3 must be a valid command i.e found in the PATH) 

And last

# Directly point to any version of python binary, this can be even another virtualenv's bin/python. $ virtualenv -p /path/to/any/bin/python new_env 

Alternatively, I think you could use the specific version of Python itself to create the virtual environment. That way, you'll know for sure it's the correct version:

$ python3.5 -m venv test35$ ./test35/bin/pythonPython 3.5.2 (v3.5.2:4def2a2901a5, Jun 26 2016, 10:47:25)[GCC 4.2.1 (Apple Inc. build ) (dot 3)] on darwinType "help", "copyright", "credits" or "license" for more information.>>>

Reference at https://docs.python.org/3.5/library/venv.html

As of version 3.3, python includes a package named venv. However that package doesn't provide the same functionalities as the traditional virtualenv package.

venv allows creating virtual environments only for the version of python it's installed for.virtualenv allows creating virtual environments for different versions of python by providing the path to the binary.

Creating virtual envs for different versions of python:

So assuming one has python 2.7 and python 3.6 installed in /path/to/ and wants to create the virtual env named respectively env-py36 with python 3.6 and env-py27 with python 2.7

# create a virtual env with python3's venv :/path/to/python36/bin/python3 -m venv /my/python-venvs/env-py36. /my/python-venvs/env-py36/bin/activate# we're now running python 3's "env-py36" virtual env, we want to install the "virtualenv" packagepip install virtualenvdeactivate# now use virtualenv to create a virtual environment for python 2.7/my/python-venvs/env-py36/bin/virtualenv --python=/path/to/python27/bin/python /my/python-venvs/env-py27

Using python 3.3+ venv

Python 3.3+ :

/path/to/python3/bin/python3 -m venv ENV_DIR

Python 3.3 to 3.5 (deprecated in 3.6+) :

/path/to/python3/bin/pyvenv ENV_DIR

Sources:

• Creating Virtual Environments
• Python 3.3 venv
• Python virtualenv package