How to specify python version used to create Virtual Environment?
PythonPython 3.xVirtualenvPython Problem Overview
My Python virtual environments use python3.6
when I create them using virtualenv
>~ $ virtualenv my_env
but I need to use python3.5
as 3.6 is not currently supported by Opencv3
.
I've tried using the --python=<py_version>
flag when creating a virtual environment but this doesn't work.
virtualenv
for Mac and/or Linux?
How do I specify the python (3.x) version to install using Python Solutions
Solution 1 - Python
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
Solution 2 - Python
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/python
Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 26 2016, 10:47:25)
[GCC 4.2.1 (Apple Inc. build ) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>
Reference at https://docs.python.org/3.5/library/venv.html
Solution 3 - Python
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" package
pip install virtualenv
deactivate
# 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:
Solution 4 - Python
I working on all ubuntu and MacOS
> Ubuntu : virtualenv -p python3.6 environment_file
>
> Mac OS : virtualenv -p python3.6 environment_file
I think it be same
Solution 5 - Python
I had this issue (and came here) but under Windows. Python 3.9 was installed on one system but it had issues with code developed under 3.7. I wanted to use a virtual environment to downgrade to 3.7 to help debug the issue. Using Python Launcher for Windows:
py -3.7 -m venv my_env
in the python project folder did the trick for me.