Use different Python version with virtualenv

Question

I have a Debian system currently running with python 2.5.4. I got virtualenv properly installed, everything is working fine. Is there a possibility that I can use a virtualenv with a different version of Python?

I compiled Python 2.6.2 and would like to use it with some virtualenv. Is it enough to overwrite the binary file? Or do I have to change something in respect to the libraries?

Answer 1

Just use the --python (or short -p) option when creating your virtualenv instance to specify the Python executable you want to use, e.g.:

virtualenv --python=/usr/bin/python2.6 <path/to/new/virtualenv/>

N.B. For Python 3.3 or later, refer to The Aelfinn's answer below.

Answer 2

UPDATE: For Python3.6, the below pyvenv script is deprecated. Instead, the Python Docs suggest creating the virtual environment with the following command:

python3 -m venv <myenvname>

For python3 (3.3+), use either the above method or the script pyvenv command.

pyvenv /path/to/new/virtual/environment

Please note that venv does not permit creating virtualenv with other versions of Python. For that, install and use the virtualenv package.

Answer 3

These are steps when you are on shared hosting environment and need to install & complie Python from source and then create venv from your Python version. For Python 2.7.9 you would do something along these lines:

mkdir ~/src
wget http://www.python.org/ftp/python/2.7.9/Python-2.7.9.tgz
tar -zxvf Python-2.7.9.tgz
cd Python-2.7.9
mkdir ~/.localpython
./configure --prefix=$HOME/.localpython
make
make install

virtual env

cd ~/src
wget https://pypi.python.org/packages/5c/79/5dae7494b9f5ed061cff9a8ab8d6e1f02db352f3facf907d9eb614fb80e9/virtualenv-15.0.2.tar.gz#md5=0ed59863994daf1292827ffdbba80a63
tar -zxvf virtualenv-15.0.2.tar.gz
cd virtualenv-15.0.2/
~/.localpython/bin/python setup.py install
virtualenv ve -p $HOME/.localpython/bin/python2.7
source ve/bin/activate   

Naturally this can be applicable to any situation where you want to replicate the exact environment you work and deploy on.

Answer 4

virtualenv --python=/usr/bin/python2.6 <path/to/myvirtualenv>

Answer 5

There is an easier way,

virtualenv venv --python=python2.7

Thanks to a comment, this only works if you have python2.7 installed at the system level (e.g. /usr/bin/python2.7).

Otherwise, if you are using homebrew you can use the path to give you what you want.

virtualenv venv --python=/usr/local/bin/python

You can find the path to your python installation with

which python

This will also work with python 3.

which python3
>> /usr/local/bin/python3
virtualenv venv --python=/usr/local/bin/python3

Ultimately condensing to:

virtualenv venv -p `which python`
virtualenv venv -p `which python3`

Answer 6

Under Windows for me this works:

virtualenv --python=c:\Python25\python.exe envname

without the python.exe I got WindowsError: [Error 5] Access is denied I have Python2.7.1 installed with virtualenv 1.6.1, and I wanted python 2.5.2.

Answer 7

Mac OSX 10.6.8 (Snow Leopard):

1) When you do pip install virtualenv, the pip command is associated with one of your python versions, and virtualenv gets installed into that version of python. You can do

 $ which pip   

to see what version of python that is. If you see something like:

 $ which pip
 /usr/local/bin/pip

then do:

$ ls -al /usr/local/bin/pip
lrwxrwxr-x  1 root  admin  65 Apr 10  2015 /usr/local/bin/pip ->
../../../Library/Frameworks/Python.framework/Versions/2.7/bin/pip

You can see the python version in the output.

By default, that will be the version of python that is used for any new environment you create. However, you can specify any version of python installed on your computer to use inside a new environment with the -p flag:

$ virtualenv -p python3.2 my_env  
Running virtualenv with interpreter /usr/local/bin/python3.2  
New python executable in my_env/bin/python  
Installing setuptools, pip...done.  

virtualenv my_env will create a folder in the current directory which will contain the Python executable files, and a copy of the pip [command] which you can use to install other packages.

http://docs.python-guide.org/en/latest/dev/virtualenvs/

virtualenv just copies python from a location on your computer into the newly created my_env/bin/ directory.

2) The system python is in /usr/bin, while the various python versions I installed were, by default, installed into:

 /usr/local/bin

3) The various pythons I installed have names like python2.7 or python3.2, and I can use those names rather than full paths.

========VIRTUALENVWRAPPER=========

1) I had some problems getting virtualenvwrapper to work. This is what I ended up putting in ~/.bash_profile:

export WORKON_HOME=$HOME/.virtualenvs
export PROJECT_HOME=$HOME/django_projects  #Not very important -- mkproject command uses this
#Added the following based on: 
#http://stackoverflow.com/questions/19665327/virtualenvwrapper-installation-snow-leopard-python
export VIRTUALENVWRAPPER_PYTHON=/usr/local/bin/python2.7 
#source /usr/local/bin/virtualenvwrapper.sh
source /Library/Frameworks/Python.framework/Versions/2.7/bin/virtualenvwrapper.sh

2) The -p option works differently with virtualenvwrapper: I have to specify the full path to the python interpreter to be used in the new environment(when I do not want to use the default python version):

$ mkvirtualenv -p /usr/local/bin/python3.2 my_env
Running virtualenv with interpreter /usr/local/bin/python3
New python executable in my_env/bin/python
Installing setuptools, pip...done.
Usage: source deactivate

removes the 'bin' directory of the environment activated with 'source
activate' from PATH. 

Unlike virtualenv, virtualenvwrapper will create the environment at the location specified by the $WORKON_HOME environment variable. That keeps all your environments in one place.

Answer 8

Suppose you currently have python 2.7 installed in your virtualenv. But want to make use of python3.2, You would have to update this with:

$ virtualenv --python=/usr/bin/python3.2 name_of_your_virtualenv

Then activate your virtualenv by:

$ source activate name_of_your_virtualenv

and then do: python --version in shell to check whether your version is now updated.

Answer 9

These two commands should work fine.

virtualenv -p python2 myenv (For python2)

virtualenv -p python3 myenv (For python3)

Answer 10

You can call virtualenv with python version you want. For example:

python3 -m virtualenv venv

Or alternatively directly point to your virtualenv path. e.g. for windows:

c:\Python34\Scripts\virtualenv.exe venv

And by running:

venv/bin/python

Python 3.5.1 (v3.5.1:37a07cee5969, Dec  5 2015, 21:12:44) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

you can see the python version installed in virtual environment

Answer 11

The -p approach works well, but you do have to remember to use it every time. If your goal is to switch to a newer version of Python generally, that's a pain and can also lead to mistakes.

Your other option is to set an environment variable that does the same thing as -p. Set this via your ~/.bashrc file or wherever you manage environment variables for your login sessions:

export VIRTUALENV_PYTHON=/path/to/desired/version

Then virtualenv will use that any time you don't specify -p on the command line.

Answer 12

For Mac(High Sierra), install the virtualenv on python3 and create a virtualenv for python2:

 $ python3 -m pip install virtualenv
 $ python3 -m virtualenv --python=python2 vp27
 $ source vp27/bin/activate
 (vp27)$ python --version
 Python 2.7.14

Answer 13

Even easier, by using command substitution to find python2 for you:

virtualenv -p $(which python2) <path/to/new/virtualenv/>

Or when using virtualenvwrapper :

mkvirtualenv -p $(which python2) <env_name>

Answer 14

On the mac I use pyenv and virtualenvwrapper. I had to create a new virtualenv. You need homebrew which I'll assume you've installed if you're on a mac, but just for fun:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"


brew install pyenv
pyenv install 2.7.10
pyenv global 2.7.10
export PATH=/Users/{USERNAME}/.pyenv/versions/2.7.10/bin:$PATH
mkvirtualenv -p ~/.pyenv/versions/2.7.10/bin/python  {virtual_env_name}

I also froze my requirements first so i could simply reinstall in the new virtualenv with:

pip install -r requirements.txt

Answer 15

In windows subsystem for linux:

1. Create environment for python3:

   virtualenv --python=/usr/bin/python3 env
   

2. Activate it:

   source env/bin/activate
   

Answer 16

Yes, the above answers are correct and works fine on Unix based systems like Linux & MAC OS X.

I tried to create virtualenv for Python2 & Python3 with the following commands.

Here I have used venv2 & venv3 as their names for Python2 & Python3 respectively.

Python2 »

MacBook-Pro-2:~ admin$ virtualenv venv2 --python=`which python2`
Running virtualenv with interpreter /usr/local/bin/python2
New python executable in /Users/admin/venv2/bin/python
Installing setuptools, pip, wheel...done.
MacBook-Pro-2:~ admin$ 
MacBook-Pro-2:~ admin$ ls venv2/bin/
activate        easy_install        pip2.7          python2.7
activate.csh        easy_install-2.7    python          wheel
activate.fish       pip         python-config
activate_this.py    pip2            python2
MacBook-Pro-2:~ admin$ 

Python3 »

MacBook-Pro-2:~ admin$ virtualenv venv3 --python=`which python3`
Running virtualenv with interpreter /usr/local/bin/python3
Using base prefix '/Library/Frameworks/Python.framework/Versions/3.6'
New python executable in /Users/admin/venv3/bin/python3
Also creating executable in /Users/admin/venv3/bin/python
Installing setuptools, pip, wheel...done.
MacBook-Pro-2:~ admin$ 
MacBook-Pro-2:~ admin$ ls venv3/bin/
activate        easy_install        pip3.6          python3.6
activate.csh        easy_install-3.6    python          wheel
activate.fish       pip         python-config
activate_this.py    pip3            python3
MacBook-Pro-2:~ admin$ 

Checking Python installation locations

MacBook-Pro-2:~ admin$ which python2
/usr/local/bin/python2
MacBook-Pro-2:~ admin$ 
MacBook-Pro-2:~ admin$ which python3
/usr/local/bin/python3
MacBook-Pro-2:~ admin$ 

Answer 17

It worked for me

sudo apt-get install python3-minimal

virtualenv --no-site-packages --distribute -p /usr/bin/python3 ~/.virtualenvs/py3

Answer 18

On windows:

py -3.4x32 -m venv venv34

or

py -2.6.2 -m venv venv26

This uses the py launcher which will find the right python executable for you (assuming you have it installed).

Answer 19

virtualenv -p python3 myenv

Link to Creating virtualenv

Answer 20

For Debian (debian 9) Systems in 2019, I discovered a simple solution that may solve the problem from within the virtual environment.

Suppose the virtual environment were created via:

python3.7 -m venv myenv

but only has versions of python2 and python2.7, and you need the recent features of python3.7.

Then, simply running the command:

(myvenv) $ python3.7 -m venv --upgrade /home/username/path/to/myvenv/

will add python3.7 packages if they are already available on your system.

Answer 21

This was a bug with virtualenv. Just upgrading your pip should be the fix.

pip install --upgrade virtualenv

Answer 22

It worked for me on windows with python 2 installation :

1. Step 1: Install python 3 version .
2. Step 2: create a env folder for the virtual environment.
3. Step 3 : c:\Python37\python -m venv c:\path\to\env.

This is how i created Python 3 virtual environment on my existing python 2 installation.

Answer 23

I use pyenv to manage my python version.

pyenv install 3.7.3
pyenv local 3.7.3

Check your python version:

$ python --version
Python 3.7.3

Create the virtual environment with venv:

python -m venv .

Then activate the Virtual Environment:

source bin/activate

Check your python version:

$ python --version
Python 3.7.3

You may need to remove the previous virtual environment

rm -rf bin

Answer 24

You can do it by doing this:

virtualenv -p python3 .

Answer 25

Yes you just need to install the other version of python, and define the location of your other version of python in your command like :

virtualenv /home/payroll/Documents/env -p /usr/bin/python3

Answer 26

Here is the stepbystep how to create the Virtual environment in Visual Studio Code folder: I used Powershell (Administrator mode):
1. I create a VSCode folder - "D:\Code_Python_VE" where I want to create Virtual environment.
2. Next I type the command - "pip3 install virtualenv". (D:\Code_Python_VE> pip3 install virtualenv ) 3. D:\Code_Python_VE> python3 -m venv project_env
4. D:\Code_Python_VE>project_env\Scripts\activate.bat
5. D:\Code_Python_VE> ls - This will list a new directory "project_env".
6. D:\Code_Python_VE> code . This will start Visual Studio Code. Make sure the command is (code .).
7. Create launch.jason with following content:

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "type": "python",
            "request": "launch",
            "name": "Python: Current File (Integrated Terminal 1)",
            "program": "${file}"
        },
        {
            "name": "Python: Current File (Integrated Terminal 2)",
            "type": "python",
            "request": "launch",
            "program": "${file}",
            "console": "integratedTerminal"
        },
    ]
}

(Please search how to go to Debug window and Add new Configuration in VS Code).

8. Press F1 in Visual studio code and the command pallet will open - Select Python Interpreter and select the virtual environment project_env.
9. Add test.py file with one statement print("Hello World").
10. Run this program.
11. In Visual studio Code terminal -
    (project_env) d:\Code_Python_VE>python -m pip install --upgrade
    I hope this helps.