I have Python 3.7 && I would like to create a python 2.7 virtual environment to run some code that only works on python 2.7
How do I create this python 2.7 virtual environment?
python3 -m venv ?
When creating virtual environment, a pyvenv.cfg is created that has home key which tells where the python executable is, which was used to create the virtual environment. If your global python installation is version 3.8.6, and you run
python3 -m venv something
you will create virtual environment in folder something, that has pyvenv.cfg that points to the python executable of the Python 3.8.6 installation. There is no easy way* to make it point to the Python 2.7 executable.
What can you do?
virtualenv as venv replacement
The venv module was introduced in Python 3.3, so you cannot use it to create virtual environments with python 2.7. You could use the virtualenv package which is a superset of venv. First, install it with python 2.7**:
python -m pip install virtualenv
If Python 2.7 is not on your PATH as python, use full path to the python executable in place of python. Then, you can create virtual environments that have Python 2.7 with
virtualenv something
or
virtualenv --python=python2.7 something
* It is not supported by the venv module out of the box, at least.
** You can actually install it with any Python version, but then you will have to specify --python=/opt/python-2.7/bin/python or --python=python2.7 when running virtualenv. By default, it uses the python executable that was used to install it.
venv doesn’t allow creating virtual environments with other versions of Python than the one currently installed. You would have to use the traditional virtualenv package which allows creating virtual environments for different versions of python by providing the path to the binary like this:
virtualenv --python=/usr/bin/python2.7 /path/to/virtualenv/
where the path /usr/bin/python2.7 refers to the path of the binary for Python 2.7 on your system.
Install python2.7
Add universe repo
sudo apt-add-repository universe
sudo apt update
Install python2.7
sudo apt install python2-minimal
Create virtualenv with python2.7
mkvirtualenv -p $(which python2) something
Related
I have different venvs in my machine in which I have python 3.10.
Now for a specific project, I realised that python 3.10 is not suitable as some libraries are still not compatible. Therefore when creating a new venv for a new project, I would like to downgrade python, say to 3.8, only for this specific venv.
How can I do that?
What should I type onto the terminal to do this?
PS: I use VS and its terminal to create venv
The recommended way by python.org
The recommended way of managing virtual environments since Python 3.5 is with the venv module within the Python Standard Library itself.
Source: https://docs.python.org/3/library/venv.html#creating-virtual-environments
That is not the same as virtualenv, which is a third party package, outside the Python Standard Library.
Source: https://pypi.org/project/virtualenv/
Dangerous to downgrade (and to upgrade)
Depending on if your system itself uses Python, it could be dangerous for system stability to change the system Python version. Your system might need exactly that version of Python. That is true with Ubuntu.
Install another version of Python
Safer than downgrading or upgrading is installing other versions of Python on the same system.
For example, in Ubuntu 20.04, to install Python 3.9:
# Update package lists
me#mydevice:~$ sudo apt update
# Add the deadsnakes repository
me#mydevice:~$ sudo add-apt-repository ppa:deadsnakes/ppa
# Install Python 3.9
me#mydevice:~$ sudo apt install python3.9
Install the venv package and create a venv virtual environment
# Install the venv package for Python 3.9
me#mydevice:~$ sudo apt install python3.9-venv
# Make a folder for venv virtual environments
me#mydevice:~$ mkdir ~/.venvs
# Create a new venv virtual environment with Python 3.9 in it
me#mydevice:~$ python3.9 -m venv ~/.venvs/my-venv-name
# Activate the new venv
me#mydevice:~$ source ~/.venvs/my-venv-name/bin/activate
(my-venv-name) me#mydevice:~$
Check versions within the venv virtual environment
# Check the Python version inside the venv:
(my-venv-name) me#mydevice:~$ python -V
Python 3.9.9
# Check the Pip version inside the venv:
(my-venv-name) me#mydevice:~$ pip3 --version
pip 21.2.4 from /home/me/.venvs/my-venv-name/lib/python3.9/site-packages/pip (python 3.9)
Deactivate the venv virtual environment
(my-venv-name) me#mydevice:~$ deactivate
me#mydevice:~$
Check versions outside any virtual environments
# Check Python version:
me#mydevice:~$ python -V
Python 3.8.10
# Check the Pip version:
me#mydevice:~$ pip3 --version
pip 20.0.2 from /home/me/.venvs/my-venv-name/lib/python3.8/site-packages/pip (python 3.8)
Install more Python versions
To install more Python versions, just change the version number from 3.9 to which ever version you choose, that is available from the deadsnakes repository.
I believe the best way to work with different python versions in isolation is pyenv, managing virtual environments can be done with pyenv-virtualenv.
I think this article from Real Python does a good job at explaining how to manage different python versions as well as different virtual environments.
For posterity, with the tools mentioned above you can do the following (once the proper python versions are installed)
pyenv virtualenv <python_version> <environment_name>
# Then activate it
pyenv local <environment_name>
Now that you've created a virtual environment in the folder, it should be picked up any time you enter the folder. VSCode should also pick it up, as per its documentation.
P.S: The reason I think it's a good approach it's because it allows you to manage python versions as well as environments with a single tool. Each version is installed only once, in one place, which should help because it reduces complexity.
Simple and recent
Supposed that you have a different version of Python installed in your system. To check use the following command to check:
> py --list
-3.10-64 *
-3.7-64
And you want to create a new virtual environment for python 3.7 on a 'test_env' directory. Run the following command:
> py -3.7 -m venv test_env
Then activate the test_env by running the following command on Windows PowerShell:
> .\test_env\Scripts\Activate.ps1
Or Linux:
$ source test_env/bin/activate
Check:
python --version
Python 3.7.0
You can have multiple python versions installed at the same time and you can create virtual environments with the needed version. Make sure you have installed the python version you need and then specify its location when you create the virtual environment:
virtualenv -p <path-to-new-python-installation> <new-venv-name>
Example:
virtualenv -p C:\Users\ssharma\AppData\Local\Programs\Python\Python38\python.exe venv38
This will create a virtual environment called venv38 with Python 3.8.
you can do it by using "virtualenv" library. It can be installed with command pip install virtualenv
then followed by command
virtualenv "name_of_your_environment" #no quotes
and then use the following code to activate your venv
"name_of_your_environment"\Scripts\activate #NOTE YOU MUST BE at your directory where you created your env.
its for VS CODE but I prefer installing conda and then creating env on conda prompt using conda which later you can access to vs code to and its easy to activate that env from anywhere just type conda activate 'name_of_your_env' on vs terminal
You can use anaconda:
conda create -n mypython3.8 python=3.8
For merely the sake of enough porridge in your stew.
Can the virtualenv command installed by pip3 install virtualenv be used to safely create python2 environments (E.G. python3 -m virtualenv -p "$(which python2)" venv2 and vice versa?
Yes, I use that all the time. I have one version of virtualenv and create virtual environments for many Python versions from 2.7 to 3.6 and also for PyPy.
On Mac, if I simply open a new terminal window and run:
python --version
I get:
3.6
but if I do this:
virtualenv venv && source venv/bin/activate
and then, in that environment, I run :
python --version
I get:
2.7
I need virtualenv to run 3.6. How do I do that?
This :
/usr/bin/python
is 2.7 but this:
/usr/local/bin/python
is 3.6. The path for my normal user has /usr/local/bin come up before /usr/bin/. Is virtualenv running as someone else? How do I control its path?
I ran this:
virtualenv -p /usr/local//Cellar/python/3.6.5/bin/python3 venv
but then I do this:
virtualenv venv && source venv/bin/activate
and I'm running in an environment with 2.7.
On Python 3 you don't need virtualenv script anymore, you should just use the venv module included with standard lib:
python3 -m venv myvenv
But if you really want to keep using the old virtualenv script, you can - specify the interpreter explicitly with the -p option:
virtualenv -p /path/to/python3 myvenv
The easiest way is to change python globally to Python3 as I think you're using it more often than Python 2.7 (or hopefully always). To achieve this, add the following line of code at the end of your .bash_profile:
alias python='python3'
virtuanenv is using /usr/bin/python, hence it should work now.
If you don't want to change it globally, than you should use the following command to create your Python3.6 virtual environment:
python3 -m venv venv
or the explicit Python version if you have multiple Python3 versions installed:
python3.6 -m venv venv
On more suggestion at the end: I recommend you to read something about pipenv as it's the new recommended way to handle virtual environments and your whole package management at once. It's super easy and fixes a lot of common issues. Here's a nice article from realpython.com on that topic.
Hope I could help you. Have a nice day.
I have two versions of Python in my laptop. Python 2.7 and Python 3.6. If install a module this is installed only in Python 3.6.
I would like to install modules in Python 2.7 through pip but I don't know how to do it.
I want to install right now GDAL and Fiona for Python 2.7 in Ubuntu 17.04.
If Python 2.7 is well installed on your system, you should have python2 and/or python2.7 commands and you could run the following:
python2.7 -m pip install <your-packages>
To make sure you are running the correct python version, you can use python2.7 --version
Better use virtual environment for this.
Follow this link https://realpython.com/blog/python/python-virtual-environments-a-primer/
You can set python version to use in virtual env using
virtualenv -p path/to/python2.7 env_name
Activate this env using . env_name/bin/activate then,
Use pip install package_name to install libraries inside virtual environment
I'm using Fedora 21. Installed the python3-tkinter package using yum install python3-tkinter. The package gets stored in the /usr/lib64/python3.4 directory. Is there a way to use pip to install tkinter?
Have a virtualenv setup with python3. When I try to run my program within that virtualenv I get:
ImportError: No module named 'tkinter'.
Does it make sense to copy the package directories from /usr/lib64/python3.4 to the site_packages folder associated with the virtualenv?
I was using python 3.3.2 interpreter. Turns out the default packages installed when running the command yum install python3-tkinter are set to work with python 3.4.1 interpreter. Configuring my virtualenv to use the python 3.4.1 interpreter proved to be the solution as the python interpreter was then able to find the required libraries in it's path.