On command $which python3$ , the location says /opt/homebrew/bin/python3 on my Mac. Is this okay for python to be in other directory than /usr/local/ ?
Yes. It will work. I mean if you change the location of installation directory, mac os will recognize it and python3 instruction will work.
Yeah it's absolutely ok. But it's better to create a project wise virtual env so that you don't messed up installing so many third party libraries globally in your system which could break system tools and other projects.
Installing vitualenv:
python3 -m pip install --user virtualenv
Creating a virtual environment.
cd {{your project directory}}
python3 -m venv env
Activate the virtualenv:
source env/bin/activate
Now if you run which python you will see the python is from your newly created virtual env.
This has been driving me crazy for the past 2 days.
I installed virtualenv on my Macbook using pip install virtualenv.
But when I try to create a new virtualenv using virtualenv venv, I get the error saying "virtualenv : command not found".
I used pip show virtualenv and the location of the installation is "Location: /usr/local/lib/python2.7/site-packages" but I can't figure out where the executable is. I tried dozens other similar looking posts but those solutions do not work for me.
Any ideas what might be going wrong here?
The only workable approach I could figure out (with help from #Gator_Python was to do python -m virtualenv venv. This creates the virtual environment and works as expected.
I have custom python installed and maybe that's why the default approach doesn't work for me.
On macOS Mojave
First check python is in the path.
python --version
Second check pip is installed.
pip --version
If it is not installed.
brew install pip
Third install virtualenv
sudo -H pip install virtualenv
For Python 3
python3 -m virtualenv venv
As mentioned in the comments, you've got the virtualenv module installed properly in the expected environment since python -m venv allows you to create virtualenv's.
The fact that virtualenv is not a recognized command is a result of the virtualenv.py not being in your system PATH and/or not being executable. The root cause could be outdated distutils or setuptools.
You should attempt to locate the virtualenv.py file, ensure it is executable (chmod +x) and that its location is in your system PATH. On my system, virtualenv.py is in the ../Pythonx.x/Scripts folder, but this may be different for you.
Could it be that you are using Anaconda package manager? If so, then it has it's own virtual environment system which you setup as follows:
conda create --name venv
I had the same issue (although on ubuntu), a simple solution is instead of doing pip install virtualenv, you precede the commend with "sudo".
A little inspection reveals the reason behind this fix:
pip install virtualenv tries to put an executable under /usr/local/bin so that it can be invoked from command line, but it failed because only root has write permission to that directory
an alternative is pip install --user virtualenv, here are some further readings 1,2
Had the same problem on Windows. Command not found and can't find the executable in the directory given by pip show.
Fixed it by adding "C:\Users{My User}\AppData\Roaming\Python\Python39\Scripts" to the PATH environment variable.
Install virtualenv from https://pypi.org/project/virtualenv
python -m pip install --user virtualenv
sudo /usr/bin/easy_install virtualenv
I succeded creating manually a link to location/virtualenv.py in /usr/local/bin, naming it virtualenv and adding +x attribute on file
➜ ~ pip show virtualenv
Name: virtualenv
Version: 16.6.0
Summary: Virtual Python Environment builder
Home-page: https://virtualenv.pypa.io/
Author: Ian Bicking
Author-email: ianb#colorstudy.com
License: MIT
Location: /home/prsadev/.local/lib/python2.7/site-packages
Requires:
~ chmod +x /home/prsadev/.local/lib/python2.7/site-packages/virtualenv.py
~ sudo ln -sf /home/prsadev/.local/lib/python2.7/site-packages/virtualenv.py /usr/local/bin/virtualenv
I tried to have virtualenv at a random location & faced the same issue on a UBUNTU machine, when I tried to run my 'venv'. What solved my issue was :-
$virtualenv -p python3 venv
Also,instead of using $activate try :-
$source activate
If you look at the activate script(or $cat activate), you will find the same in comment.
This solved my similar problem!
You need to look online on how to create a virtual environement with python X.X.X (replace x.x.x with your python version)
mine was python 3.4.3 so bellow is how should i deal with it:
sudo python3 -m venv aramisvenv
I use asdf and had to do a reshim after installing virtualenv. asdf reshim
Fixed due to this response
Using virtualenv, I run my projects with the default version of Python (2.7). On one project, I need to use Python 3.4.
I used brew install python3 to install it on my Mac. Now, how do I create a virtualenv that uses the new version?
e.g. sudo virtualenv envPython3
If I try:
virtualenv -p python3 test
I get:
Running virtualenv with interpreter /usr/local/bin/python3
Using base prefix '/usr/local/Cellar/python3/3.4.0_1/Frameworks/Python.framework/Versions/3.4'
New python executable in test/bin/python3.4
Also creating executable in test/bin/python
Failed to import the site module
Traceback (most recent call last):
File "/Users/user/Documents/workspace/test/test/bin/../lib/python3.4/site.py", line 67, in <module>
import os
File "/Users/user/Documents/workspace/test/test/bin/../lib/python3.4/os.py", line 634, in <module>
from _collections_abc import MutableMapping
ImportError: No module named '_collections_abc'
ERROR: The executable test/bin/python3.4 is not functioning
ERROR: It thinks sys.prefix is '/Users/user/Documents/workspace/test' (should be '/Users/user/Documents/workspace/test/test')
ERROR: virtualenv is not compatible with this system or executable
simply run
virtualenv -p python3 envname
Update after OP's edit:
There was a bug in the OP's version of virtualenv, as described here. The problem was fixed by running:
pip install --upgrade virtualenv
Python 3 has a built-in support for virtual environments - venv. It might be better to use that instead. Referring to the docs:
Creation of virtual environments is done by executing the pyvenv
script:
pyvenv /path/to/new/virtual/environment
Update for Python 3.6 and newer:
As pawciobiel correctly comments, pyvenv is deprecated as of Python 3.6 and the new way is:
python3 -m venv /path/to/new/virtual/environment
I'v tried pyenv and it's very handy for switching python versions (global, local in folder or in the virtualenv):
brew install pyenv
then install Python version you want:
pyenv install 3.5.0
and simply create virtualenv with path to needed interpreter version:
virtualenv -p /Users/johnny/.pyenv/versions/3.5.0/bin/python3.5 myenv
That's it, check the version:
. ./myenv/bin/activate && python -V
There are also plugin for pyenv pyenv-virtualenv but it didn't work for me somehow.
Install prerequisites.
sudo apt-get install python3 python3-pip virtualenvwrapper
Create a Python3 based virtual environment. Optionally enable --system-site-packages flag.
mkvirtualenv -p /usr/bin/python3 <venv-name>
Set into the virtual environment.
workon <venv-name>
Install other requirements using pip package manager.
pip install -r requirements.txt
pip install <package_name>
When working on multiple python projects simultaneously it is usually recommended to install common packages like pdbpp globally and then reuse them in virtualenvs.
Using this technique saves a lot of time spent on fetching packages and installing them, apart from consuming minimal disk space and network bandwidth.
sudo -H pip3 -v install pdbpp
mkvirtualenv -p $(which python3) --system-site-packages <venv-name>
Django specific instructions
If there are a lot of system wide python packages then it is recommended to not use --system-site-packages flag especially during development since I have noticed that it slows down Django startup a lot. I presume Django environment initialisation is manually scanning and appending all site packages from the system path which might be the reason. Even python manage.py shell becomes very slow.
Having said that experiment which option works better. Might be safe to just skip --system-site-packages flag for Django projects.
virtualenv --python=/usr/bin/python3 <name of env>
worked for me.
This is all you need, in order to run a virtual environment in python / python3
First if virtualenv not installed, run
pip3 install virtualenv
Now Run:
virtualenv -p python3 <env name> # you can specify full path instead <env_name> to install the files in a different location other than the current location
Sometime the cmd virtualenv fails, if so use this:
python3 -m virtualenv <env_name> # you can specify full path instead <env_name> to install the files in a different location other than the current location
Now activate the virtual env:
source <env_name>/bin/activate
Or:
source `pwd`/<env_name>/bin/activate
Now run
which python
You should see the full path to your dir and <env_name>/bin/python suffix
To exit the virtualenv, run:
deactivate
To troubleshoot Python location got to here
You can specify specific Version of Python while creating environment.
It's mentioned in virtualenv.py
virtualenv --python=python3.5 envname
In some cases this has to be the full path to the executable:
virtualenv --python=/Users/username/.pyenv/versions/3.6.0/bin/python3.6 envname
How -p works
parser.add_option(
'-p', '--python',
dest='python',
metavar='PYTHON_EXE',
help='The Python interpreter to use, e.g., --python=python3.5 will use the python3.5 '
'interpreter to create the new environment. The default is the interpreter that '
'virtualenv was installed with (%s)' % sys.executable)
I had the same ERROR message. tbrisker's solution did not work in my case. Instead this solved the issue:
$ python3 -m venv .env
In addition to the other answers, I recommend checking what instance of virtualenv you are executing:
which virtualenv
If this turns up something in /usr/local/bin, then it is possible - even likely - that you installed virtualenv (possibly using an instance of easy_tools or pip) without using your system's package manager (brew in OP's case). This was my problem.
Years ago - when I was even more ignorant - I had installed virtualenv and it was masking my system's package-provided virtualenv.
After removing this old, broken virtualenv, my problems went away.
The below simple commands can create a virtual env with version 3.5
apt-get install python3-venv
python3.5 -m venv <your env name>
if you want virtual env version as 3.6
python3.6 -m venv <your env name>
Python now comes with its own implementation of virtual environment, by the name of "venv". I would suggest using that, instead of virtualenv.
Quoting from venv - docs,
Deprecated since version 3.6: pyvenv was the recommended tool for
creating virtual environments for Python 3.3 and 3.4, and is
deprecated in Python 3.6.
Changed in version 3.5: The use of venv is now recommended for
creating virtual environments.
For windows, to initiate venv on some project, open cmd:
python -m venv "c:\path\to\myenv"
(Would suggest using double quote around directory path if it contains any spaces. Ex: "C:/My Dox/Spaced Directory/Something")
Once venv is set up, you will see some new folders inside your project directory. One of them would be "Scripts".
To activate or invoke venv you need:
C:\> <venv>\Scripts\activate.bat
You can deactivate a virtual environment by typing “deactivate” in your shell. With this, you are now ready to install your project specific libraries, which will reside under the folder "Lib".
================================ Edit 1 ====================================
The scenario which will be discussed below is not what originally asked, just adding this in case someone use vscode with python extension
In case, you use vs code with its python extension, you might face an issue with its pylint which points to the global installation. In this case, pylint won't be able to see the modules that are installed in your virtual environment and hence will show errors while importing.
Here is a simple method to get past this.
cd Workspace\Scripts
.\Activate.ps1
code .
We are basically activating the environment first and then invoking vs-code so that pylint starts within the environment and can see all local packages.
In python3.6 I tried
python3 -m venv myenv,
as per the documentation, but it was taking so long. So the very simple and quick command is
python -m venv yourenv
It worked for me on python3.6.
On Mac I had to do the following to get it to work.
mkvirtualenv --python=/usr/bin/python3 YourEnvNameHere
If you install python3 (brew install python3) along with virtualenv burrito, you can then do mkvirtualenv -p $(which python3) env_name
Of course, I know virtualenv burrito is just a wrapper, but it has served me well over the years, reducing some learning curves.
virtualenv --python=/usr/local/bin/python3 <VIRTUAL ENV NAME>
this will add python3
path for your virtual enviroment.
It worked for me
virtualenv --no-site-packages --distribute -p /usr/bin/python3 ~/.virtualenvs/py3
For those having troubles while working with Anaconda3 (Python 3).
You could use
conda create -n name_of_your_virtualenv python=python_version
To activate the environment ( Linux, MacOS)
source activate name_of_your_virtualenv
For Windows
activate name_of_your_virtualenv
I tried all the above stuff, it still didn't work. So as a brute force, I just re-installed the anaconda, re-installed the virtualenv... and it worked.
Amans-MacBook-Pro:~ amanmadan$ pip install virtualenv
You are using pip version 6.1.1, however version 8.1.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Collecting virtualenv
Downloading virtualenv-15.0.3-py2.py3-none-any.whl (3.5MB)
100% |████████████████████████████████| 3.5MB 114kB/s
Installing collected packages: virtualenv
Successfully installed virtualenv-15.0.3
Amans-MacBook-Pro:python amanmadan$ virtualenv my_env
New python executable in /Users/amanmadan/Documents/HadoopStuff/python/my_env/bin/python
Installing setuptools, pip, wheel...done.
Amans-MacBook-Pro:python amanmadan$
I wanted to keep python 2.7.5 as default version on Centos 7 but have python 3.6.1 in a virtual environment running alongside other virtual environments in python 2.x
I found the below link the best solution for the newest python version ( python 3.6.1)
https://www.digitalocean.com/community/tutorial_series/how-to-install-and-set-up-a-local-programming-environment-for-python-3.
It shows the steps for different platforms but the basic steps are
Install python3.x (if not present) for your platform
Install python3.x-devel for your platform
Create virtual environment in python 3.x
(for example $ python3.6 -m venv virenv_test_p3/ )
Activate the testenvironment for python 3.x
(for example source virenv_test_p3/bin/activate)
Install the packages which you want to use in your new python 3 virtual environment and which are supported ( for example pip install Django==1.11.2)
On Windows command line, the following worked for me. First find out where your python executables are located:
where python
This will output the paths to the different python.exe on your system. Here were mine:
C:\Users\carandangc\Anaconda3\python.exe
C:\Python27\python.exe
So for Python3, this was located in the first path for me, so I cd to the root folder of the application where I want to create a virtual environment folder. Then I run the following which includes the path to my Python3 executable, naming my virtual environment 'venv':
virtualenv --python=/Users/carandangc/Anaconda3/python.exe venv
Next, activate the virtual environment:
call venv\Scripts\activate.bat
Finally, install the dependencies for this virtual environment:
pip install -r requirements.txt
This requirements.txt could be populated manually if you know the libraries/modules needed for your application in the virtual environment. If you had the application running in another environment, then you can automatically produce the dependencies by running the following (cd to the application folder in the environment where it is working):
pip freeze > requirements.txt
Then once you have the requirements.txt that you have 'frozen', then you can install the requirements on another machine or clean environment with the following (after cd to the application folder):
pip install -r requirements.txt
To see your python version in the virtual environment, run:
python --version
Then voila...you have your Python3 running in your virtual environment. Output for me:
Python 3.7.2
For those of you who are using pipenv and want to install specific version:
pipenv install --python 3.6
I got the same error due to it being a conflict with miniconda3 install so when you type "which virtualenv" and if you've installed miniconda and it's pointing to that install you can either remove it (if your like me and haven't moved to it yet) or change your environment variable to point to the install you want.
How do you install virtualenv correctly on windows?
I downloaded virtualenv1.9.1 from here and tried installing it with:
python virtualenv.py install
but it does not appear in MyPythonPath/Scripts
I tried the same way installing virutalenvwrapper-win and it installed correctly. But I can't use it because I don't have virtualenv
python.exe: can't open file
'MyPythonPath\Scripts\virtualenv-script.py': [Errno 2 ] No such file or
directory
The suggested way to install Python packages is to use pip
Please follow this documentation to install pip: https://pip.pypa.io/en/latest/installing/
Note: Python 2.7.9 and above, and Python 3.4 and above include pip already.
Then install virtualenv:
pip install virtualenv
Since I got the same error as mentioned in the question inspite of installing with:
pip install virtualenv
I would like to add a few points, that might also help someone else solve the error in a similar way as me. Don't know if that's the best way, but for me nothing else helped.
Install virtualenv
pip install virtualenv
Move into Scripts directory
cd C:\Python27\Scripts
Create a virtual env.
python virtualenv.exe my_env
Activate the virtual env.
my_env\Scripts\activate.bat
Deactivate the virtual env.
my_env\Scripts\deactivate.bat
install virtualenv
pip install virtualenv
create a virtual environment
python -m virtualenv demoEnv
Activate the environment
demoEnv\Scripts\activate
To deactivate
deactivate
There is an other way to install Python packages.
1: download the package, you want
2: open commander (press the win start-button and search for cmd)
3: cd into the folder where you downloaded your package
4: type: "python setup.py install"
For installing virtualenv, you'll have to either install it using pip as mentioned in the answer by woozyking or you'll have to do something like this:
$ curl -O https://pypi.python.org/packages/source/v/virtualenv/virtualenv-1.9.1.tar.gz
$ tar xvfz virtualenv-1.9.1.tar.gz
$ cd virtualenv-1.9.1
$ [sudo] python setup.py install
The command which you have used can be used to create a virtualenv. I would recommend you go through these small videos on virtualenv and virtualenvwrapper to get a better understanding:
python-power-tools-virtualenv
virtualenvwrapper
Creating a Virtual Environment on Windows
1. Create a virtual environment
python -m venv myenv
2. Activate
.\myenv\Scripts\activate
3. Extra information
To disable write
deactivate
These commands will also work on windows
myenv\Scripts\activate
myenv\Scripts\activate.bat
.\myenv\Scripts\activate.bat
Be careful with slashes:
myenv/Scripts/activate.bat
I prefer using this naming:
python -m venv .venv
.venv\Scripts\activate
4. Screenshot
5. Sources
https://code.visualstudio.com/docs/python/tutorial-django
https://code.visualstudio.com/docs/python/tutorial-flask
I initialize my project with virtualenv through these steps(in Windows 7 OS):
$ cd myproject
$ virtualenv venv
$ venv\scripts\activate
and then I try to install flask
$ pip install Flask
but I found the flask isn't install in my /venv/lib/site-packages folder
it is still install in my C:/Python27/lib/site-packages folder
Is this correct? I think it should be install in the venv folder
If this is incorrect, what should I do?
Try using the Scripts\pip.exe in your venv folder.
Start over with CMD. Recreate your virtualenv using only CMD. Then do a pip freeze. Things should work now. The reason why git-bash does not work is because it has only the PATH for git, and nothing else.