A while ago I had both Python 2.7 and 3.5 installed on my Mac and was able to use them both successfully. Not too long ago, I installed Anaconda and IPython. I have used those for a couple weeks for prototyping and in-console programming.
After I went back to the regular Python for my Django and Flask projects, I discovered an unpleasant thing. Namely, whenever I try to run python or python3 I get the following error:
dyld: Library not loaded: #executable_path/../.Python
Referenced from: /Users/name/anaconda3/bin/python3
Reason: image not found
Abort trap: 6
When I run conda I also get the same error.
If I create a new virtual environment with virtualenv django-project, I am able to activate it, and it allows me to run Python 2.7 successfully.
My question is the following: How can I fix python and python3 for the command line while also retaining the working Anaconda and IPython? How can I make sure that the virtual environments are able to carry Python 3?
I also use macOS and I never mess with or even deal with the system python. I've installed python3 via Homebrew (https://brew.sh) and I always use a virtual environment. I have one in my home directory (my default) and I have one for each project I'm working on.
Your rule of thumb should be to never run 'pip' if you aren't within a virtualenv. Check with $ echo $VIRTUAL_ENV.
To create/recreate the virtual environment in python3 with the currently installed libraries:
Get into your project directory and active your virtualenv.
(optional) Dump your requirements via pip: $ pip freeze > requirements.txt
Nuke your virtual environment directory if you have one: $ rm -rf .venv
Deactivate it: $ deactivate
Create a new one with python3: $ virtualenv -p python3 .venv
Activate it: $ source .venv/bin/activate
(optional) Install your requirements: $ pip install -r requirements.txt
Profit.
You can skip the steps for writing and reading the requirements.txt if you just want to create a new virtual environment and then install only the modules you want/need later.
firstly, to reduce your confusion n which python you are using you could try the following 2 commands in Linux or mac where bash shell is installed:
$ which python
or
$ which python3
in my case, it outputs the python paths I am using with pyenv [with fish shell] [$ is a shell sign]
Related
I use Windows 10. I was trying to pip install Vectorbt but the installation could not have been finished because there was an error when numba and llvmlite were suppose to be installed. I was using Python 3.10 and read that there is a compatibility problem with it. So I uninstalled it and installed Python 3.8.7. Afterwards I made sure that the system variable is set on the proper Python path. I closed everything and even restarted the system but in the command line or the powershell terminal in VSC I get the error "No Python at" and the directory of the previous 3.10 installation.
The variable is set corectly (was set as an admin).
Any ideas?
Maybe something with the registry?
Thanks!
I can recommend you use virtual environments to manage python versions (you'll never look back), high level steps:
cd mydir
virtualenv .venv # creates a virtual env dev (or python3 -m venv .venv)
source .venv/bin/activate # activates the virtual env
pip install -r requirements.txt # installs the required dependencies
python -m pytest # runs the unit tests
More details in the docs: https://docs.python.org/3/library/venv.html
I am trying to create a virtual environment to run a script which requires Python 3.6. I started off with Pipenv but I am unable to create the same environment on other platforms via the Pipfile.lock or requirements.txt unless the other platform(s) has Python 3.6 installed. I have read this post but I am unsure which direction I should take to create a virtual environment which can be shared and run its own version of Python independent of operating system and version of Python installed on the other platform.
Virtual environments are not portable, they depend on the Python installation you have.
You can't share/distribute virtual environment with others, because you can't control which version of Python others are using.
If you want to distribute your code along with all dependencies including the specific version of Python interpreter, you can use PyInstaller. It is far from perfect and little bit hacky. Also it generates a package which is specific to operating system.
https://pyinstaller.readthedocs.io/en/stable/operating-mode.html
There is also a detailed step-by-step guide on how to use PyInstaller.
https://realpython.com/pyinstaller-python/
This is step-by-step how I use Python virtual environment and share it with co-workers.
To check python and virtualenv presence, run following commands:
which python3
python3 -m pip list | grep env
which virtualenv
Install a python virtual environment builder:
python3 -m pip install virtualenv
Create a virtual environment named venv inside the project's directory: virtualenv venv
To activate this environment use this command inside project's directory: source venv/bin/activate
Install python modules dependencies listed in a requirements.txt:
python3 -m pip install -r requirements.txt
You should activate virtual environment when you working with python in this directory for package installation and for running commands in the project directory. When you need to deactivate the virtual environment do it using deactivate command.
To deactivate environment simply run: deactivate
I know there are some similar questions,but it is really hard for me to finish it.
I'm trying to create a virtualenv with python 3.7.7 in windows.
I have a downloaded python 3.7.7
C:\Users\willi\AppData\Local\Programs\Python\python-3.7.8-embed-amd64
Since I can built a virtualenv using:
python3 -m venv myenv
So I tried to modify it ,so that it can match specific python version:
python3 -m C:\Users\willi\AppData\Local\Programs\Python\python-3.7.8-embed-amd64\python.exe myenv
But it failed:
ModuleNotFoundError: No module named 'C:\\Users\\willi\\AppData\\Local\\Programs\\Python\\python-3')
Any friends can teach me how to build a virtualenv with python 3.7.7?
I think you haven't installed virtual environment in your local python
pip install virtualenv
and follow your steps. Stil, find the error. Try doing below methods, I think you will get your answer-
in command prompt
pip install virtualenv
go to the location, where you want to create your environment
cd location
virtualenv project_env_name
Now, you will find a python env in the desired location, Then go to scripts
cd project_env_name/scripts
activate
You will enter the environment you created. while leaving the environment, do
deactivate
To leave the environment.
This method works if you want to create the same python version environment as python version in your machine.
If you want to create an environment of the different version, you need to install the python of that version.
I made sure to read this question and similar ones, but I couldn't find an answer to my problems.
My problem is: when I head into muy virtual env and activate it, if I install a package there, it is also installed elsewhere in my computer.
So, for example, if I type in the terminal:
cd home/Documents/Python/tests/my_virtual_env
source bin/activate
That activates the virtual environment. If I type:
pip3 install wget #just an example package
I see the installation process and I can run a .py script that uses wget. However, why is this package also installed elsewhere in my computer?
I made sure I hadn't that package installed beforehand using pip3 list.
I confirmed that package was installed elsewhere by running a .py script from other directories (using cd /etc.etc/ to change directory and then running it from there).
I deactivated the environment in the right moment.
I also realized that if I uninstall that package within the virtualenv, it is also uninstalled elsewhere.
Thank you so much for your help.
It could be that the pip3 command being executed is not actually tied to the virtual environment. So instead you could the following, which would work whether or not the virtual environment is activated:
$ path/to/my_virtual_env/bin/python3 -m pip install SomeProject
The following command should give you a relatively clear indication of where exactly the project has been installed, make sure it is in the site-packages directory of the virtual environment:
$ path/to/my_virtual_env/bin/python3 -m pip show SomeProject
So it should show something of the sort:
Name: SomeProject
...
Location: .../path/to/my_virtual_env/lib.python3.X/site-packages
However, why is this package also installed elsewhere in my computer?
The following shows where a binary is located:
$ which somecommand
It should be relatively easy to recognize if somecommand is in a Python virtual environment or not.
I am trying to package my project with a virtual env so that it is easier to implement.
I am trying to do this in a Ubuntu bash.
I have succesfully created a Python venv using the Python virtualenv library.
I do manage to activate it using source venv_name/bin/activate.
I can indeed see (venv_name) at the beginning of my command line.
However, I do not manage to actually use this virtual environment.
I have for proof that when I type which python3 I get my root python3; and I have tried to update a package in the virtualenv but it has been updated in the root python.
What should I do to actually use my virtual env ? For now I am trying:
python3 myscript.py
And it is working but I suspect it's running with my root python3.
I think you have two versions of python (2 and 3). You create virtualenv with python 2. Recreate virtualenv with correct python version
You have to make next steps to use python3 virtual environment in Ubutnu:
1. Install virtual environment lib for python3 with command:
pip3 install virtualenv
2. Create your virtual environment:
python3 -m venv venv
3. Activate it:
source venv/bin/activate
Works correct for me in Ubutnu 16.04