I have a device with python3.7 preinstalled, in which i have installed also python3.9. I managed to change the version I am using of python3 and now the command "python3" followed by the .py file runs with python3.9.
The problem is I tried installing pandas with pip3 but it does not work (it didn't work even in the preinstalled python3.7), so I found that in debian you can install package, for example in this case pandas, using "sudo apt-get install python3-pandas" but this command keeps installing pandas in python3.7 and not in python3.9 even if now "python3" refers to python3.9.
Has anyone ever encountered this problem and has a solution?
python3.9 -m pip install pandas
Venv
You could use a virtual environment (venv) for installing dependencies.
This venv could be project specific or global.
Run python3 -m venv .venv in your project folder to create a .venv folder, which holds the venv configuration.
Run source .venv/bin/activate to activate the venv. This will link pip3 from your python 3.9 version to the pip command.
Now you can do pip install pandas to install the pandas dependency into the venv.
Conda
Another solution would be to use Anaconda or Miniconda
https://pandas.pydata.org/pandas-docs/stable/getting_started/install.html
conda create -n name_of_my_env python
This will create a minimal environment with only Python installed in
it.
To put your self inside this environment run:
source activate name_of_my_env
On Windows the command is:
activate name_of_my_env
The final step required is to install pandas. This can be done with
the following command:
conda install pandas
I have both python 2.7 and 3.8 installed in my computer but whenever I would install virtualenv using pip install virtualenvwrapper-win and then open a new virtualenv using mkvirtualenv test it says Running virtualenv with interpreter /usr/bin/python2. Now I downloaded django in the virtualenv and got the outdated version 1.11. So now I am unable to import path from django.urls among other things.
Is there any way to install vitrualenwrapper with python3 interpreter?
Please help. I am trying to learn django and this is creating a huge hassle.
Virtualenv is already included in standard library of the Python3. You can create a virtual environment using the command below:
python3 -m venv venv
The second venv is the name of your virtualenv, you can name it as you want.
To use an existing virtualenv you should use the command:
path_to_your_venv\Scripts\activate.bat
https://docs.python.org/3/library/venv.html
You can create a virtual environment for any Python version by giving the python interpreter as an argument:
mkvirtualenv -p /path/to/python_binary test
virtualenvwrapper should be installed into the same global site-packages area where virtualenv is installed. You may need administrative privileges to do that. The easiest way to install it is using pip:
pip3 install virtualenvwrapper
or:
sudo pip3 install virtualenvwrapper
I have already created a virtual env,in which python 3.4 is already installed,is there a way i can install python 3.5 in this env.i already tried pip install python3.5 ,i get -no distributions found that satisfy the requirement
run virtualenv -p python3 envname or pip install --upgrade virtualenv
You should use virtualenv command once again, this time with new python executable as a parameter:
virtualenv env -p python3.5
(supposing you previously installed virtual env into folder named env).
As you don't pass --clear parameter, your previous files will be kept inside env dir
Edit:
If you want to to use within your virtualenv a python version not installed globally on your system and don't want to install new version of python globally, you can follow these steps:
1) download and compile required version of python (not installing it via make install)
2) pass the path to new python executable to the -p parameter of virtualenv command, like virtualenv env -p /home/user/python3.5/python
I have python 3.x, and was told to install Pillow for image manipulation. After installing it with pip however, i'm unable to import PIL from the python interpreter. It just says ImportError: No module named 'PIL'. Running pip list in the command line shows that Pillow is indeed installed.
It ended up installing correctly after using easy_install instead of pip.
You might have used pip for a different python executable. To make sure that the correct pip command is used, run:
$ python3 -m pip install pillow
I don't really have the time or the means to create an entire virtual machine just for the purposes of testing this one problem.
virtualenv is not a virtual machine. All you need to create a virtualenv from scratch:
$ python3 -m pip install --user virtualenv # install package
$ python3 -m virtualenv venv # create virtualenv named 'venv'
Then to activate the created virtualenv on POSIX system:
$ source venv/bin/activate # activate on POSIX
Or on Windows:
C:\> venv\Scripts\activate
Now, python, pip commands refers to the virtualenv. To deactivate virtualenv, run:
$ deactivate
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.