I have python3.7 installed on my windows 10 laptop
But i need python3.6 for a specific project
Can i install it in virtualenv which will override python3.7 in that environment?
I don't know whether this may be an appropriate solution for you. But this is what I generally follow. Just install Anaconda in your system and create an environment according to your needs. For your case create an environment for Python 3.6.
conda create --name py36 python=3.6
//This lines will create an environment named py36
You then install libraries according to your needs in that environment. You work in that environment without interfering with the libraries of the other environment. To use anaconda kindly follow Anaconda cheatsheet. You will get everything that you need.
Related
is there a way to specify for a given python package to install in a given conda env vs. the User's python?
I thought that if I did pip install <package> in a given conda environment, this would make the package accessible in that environment.
If I create a conda environment and install pySankey then do conda list, pySankey won't show but instead be installed in /Users/username/Python/3.7/lib/python/site-packages/
The package installs with "Defaulting to user installation because normal site-packages is not writeable". I looked at other stack posts associated with this, but I'm unclear how to modify ~/.bashrc, since my understanding is that ~/.bashrc is not unique to a conda environment. I also checked the path of the conda environment but there's no local as indicated here.
This has happened to me with a couple different packages (eg these packages do not pip install into the conda environment, other do), I'm using pySankey as an example.
thanks!
I have a 2-part question about conda vs. pip virtual environments. I found great information on the answers What is the difference between pip and conda? and Does Conda replace the need for virtualenv? but still have something unclear.
I have a given python project (say PR) that I need to install and further develop on a linux server (say S) where python is installed with anaconda. Now, the usage/installation instructions of PR tell me to use python to create virtual environment and pip to install all packages. That is,
python3 -m venv PR
pip install --editable . (the dot included at the end)
According to "pip install --editable ./" vs "python setup.py develop" the latter reads the file setup.py (included in PR) which contains a function setup(...) with option install_requires listing all the required packages and installs them automatically. I have tested this on my own computer (which does not have conda) and it works fine. At least no error messages.
Now I need to further develop PR on S. My question Part 1: can I use conda instead of pip to create and update virtual environment? If yes, what would be the conda command replacing pip install --editable . ? I'm positive I will later need to install other packages as well. I'm worried about conflicts between conda/pip.
On S, I have Spyder and no other python IDEs. I have never used Spyder but I'm very familiar with PyCharm (Windows) and VS Code (Linux) so I assume debugging with Spyder will be similar to those. My question Part 2 (tied to Part 1): if I have to use pip to install packages, does Spyder see those? Or can it only see conda-installed packages?
(Edit/update): Thank you Carlos for comments. I continue my question:
I created and activated the virtual environment (VE) with conda
conda create PR_venv
conda activate PR_venv
Installed pip with
conda install pip
(this upgraded pip and installed several other packages too, including newer version of python). Installed PR and its required packages with pip
pip install -e .
Now, if I run the PR package inside this active VE interactively from the terminal, everything works fine. I would like to do the same from within spyder, to get the IDE debugging abilities in my hand.
When I start spyder, open a python file to be run, click "Run" button, it crashes in the import statements.
Spyder cannot see the installed packages. It can see only the local package PR but none of the packages installed by pip for this VE.
I am not sure what is the correct question here; I'm confused how are conda VEs related to spyder/jupyter/ipython ? I cannot find information in the conda documents about this.
I cannot find from spyder documents anything about VEs. Do I have to somehow re-install the packages (how?) inside Spyder? It seems pointless because the packages are installed already.
(Edit/Update 2): The information on https://docs.spyder-ide.org/current/installation.html makes me even more confused: Spyder is presented as both a stand-alone program and as a python package. So do I have to re-install Spyder inside the VE(?!) with
conda activate PR_venv
conda install spyder
Any clarification would be appreciated. I have always thought that the IDEs are stand-alone programs and that's it. This Spyder setup twists my brains into pretzel.
(Spyder maintainer here) About your questions:
can I use conda instead of pip to create and update virtual environment?
Yes, you can. Please see here to learn about the functionality offered by conda for managing environments.
If yes, what would be the conda command replacing pip install --editable . ?
Conda doesn't offer a good replacement for that command. However, you can still use it in a conda environment, as long as all you've installed all your package dependencies with conda before running it. That would avoid mixing conda and pip packages, which usually leads to really bad results.
if I have to use pip to install packages, does Spyder see those? Or can it only see conda-installed packages?
Spyder can work with pip and conda packages without problems. Just make sure of not mixing them (as I said above) and you'll be fine. In addition, please read our documentation to learn how to connect a local Spyder instance to a remote server.
Part 1: yes I can use conda to create VE and pip to install packages
conda create PR_venv
conda activate PR_venv
conda install pip
pip install --editable .
conda list
The last line shows which packages are installed by conda and which by pip (shown as pypi)
Part 2: spyder by default cannot see the packages. Need to do two things:
conda install spyder-kernels
Open Spyder and Tools > Preferences > Python Interpreter > Use the following interpreter > [full path to VE python command]
Restart Spyder. Now it can see the packages.
(Edit:) this link is great: https://github.com/spyder-ide/spyder/wiki/Working-with-packages-and-environments-in-Spyder
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.
I am using a CentOs Distribution of Linux and have miniconda already installed along with conda environments that I created with it. I am trying to install anaconda now. Do I have to uninstall miniconda first? I have some environments that I created with miniconda that I would like to keep. Is it possible to keep those environments if I uninstall it? The reason I need anaconda is I'd like to create environments inside my singularity container. How would it be possible to keep both? Thanks.
Both Miniconda and Anaconda include Conda, so no need to install both. Given either, a new environment with all the Anaconda distribution packages can be created using
conda create --name my_anaconda_env anaconda
Note that Python versions can be specified as part of this, e.g.,
conda create --name my_anaconda37_env anaconda python=3.7
It is well known that Anaconda installation on macOS can cause trouble with other widely used package/environment managers like Homebrew, Pyenv, Virtualenv, etc.
The majority of the solutions I've found are 'Anaconda-centric', i.e. using Anaconda as the main python manager and setup conda env for homebrew etc.
However, I am looking for a solution that's kind of 'Homebrew-centric', and setup Anaconda as a compliment. Anaconda should be set up in a way that when ever conda is used, it will work with its own Python, own packages. And leave the rest of system untouched.
The motivation for such solution is because that, for example, when one's main work-flow use homebrew Python3 (python3), homebrew pip (pip3) and Pyenv (pyenv) with requirement.txt. And occasionally using Anaconda when a project is required.
Rather than using Anaconda I would suggest using Miniconda, which includes only Python and conda (and a few support packages). Miniconda does not include all of the packages in Anaconda by default, but they can all be installed (with conda install anaconda). Once you download Miniconda, you can install it into your home folder at /Users/username/miniconda3. During the installation, you will be asked if you want to add some initialization code to your .bash_profile. Either choose yes or (if you chose no), then you can run
/Users/username/miniconda3/bin/conda init
to add the conda initialization to your .bash_profile. By default, this will activate the base environment, so you can change the default setting so the environment is not activated by default:
conda config --set auto_activate_base false
You'll probably need to open a new terminal so the conda command is available. Then, when you want to use a conda environment, you can conda activate that environment, but otherwise, conda's Python should not be on your PATH.