I have python2.7 and python3.6 installed side by side in my computer. Now when I install a package using "pip install", how can I know in which python's site-packages is my package going to be installed?
Thank you.
When you have both version 2 and 3 installations pip and pip3 differentiate the target installtion.
For installing anything on Python 3(versions 3.5 and above) use pip3
for Python 2.7 use pip
Make sure python path is set in environment variables too.
also you can use where pip or which pip as #mshsayem mentioned.
Additional Reference
if you use virtualenv, the modules are located in:
{path_to_your_virtualenv}/lib/python{your_python_version}/site-packages/
and if you don't use virtualenv, normally are installed in:
/usr/local/lib/python{your_python_version}
You have to use pip3 for install python3 modules.
Check where a specific package is installed by:
pip3 show <package_name>
List all installed packages with install locations by:
pip3 list -v
Check the install location used by default when installed without sudo:
pip3 --version
and the location for packages installed with sudo, meaning system-wide installation:
sudo pip3 --version
You can find the location of pip by which pip. Then you view the pip executable header using head `which pip` or using your preferred editor. You can find the python interpreter location on the first line. You may have a pip2 and a pip3 executable.
By the way, you can run pip as a python module by python -m pip <command>. In this way, you can specify your python interpreter.
The answer to you question is divided to two parts:
1. Which python version the native terminal selects for me?
2. How do I specify which python version to use?
Which python version the native terminal selects for me?
In windows, the default pip that will be used is the one associated with the default python version you use. You can edit it in the PATH environmental variable (Start->find-type "Environmental" and click "Edit system variables"). Look the PATH variable and see which version of python is listed. If both versions are listed, windows will select the first.
See more information on system environmental variables here.
In Ubuntu/Linux, usually pip is associated with the native legacy version (2.7), pip3 is associated with Python3.5.x and pip3.6 is associated with Python3.6.x.
However, if you are using Unix OS (such as Ubuntu) or Mac, it is highly recommended to use virtualenv and activate it. See Official documentation to see how to use it. It's true for both Python2.7 and
Python3.6. In short, you will create a lightweight copy of you python installation without any packages, and, your installed packages will be installed within this virtual environment. Once you activate a virtual environment, the pip is associated with this environment.
How do I specify which python version to use?
You have multiple choices to specify in which environment you want to install the package. It depends if you are on Windows/Linux/MAC.
Shortly, you have the following options:
Use an IDE and let it help you manage your packages (e.g. Pycharm). Using PyCharm, you will find it very easy to use its package manager. You can also open the IDE's terminal and when you use pip, it will use the package manager of the selected interpreter. See official documentation.
Use OS native terminal and specify the version. In windows, the easiest way is to go to a command line or powershell, and type "c:\path\to\python.exe -m pip install ". On Ubuntu, use pip/pip3/pip3.6. Again, on Ubuntu it is highly recommended to use venv (virtual environment) since installing wrong package on the wrong version can interrupt the native python (Ubuntu uses python for multiple reasons such as the GNOME GUI).
Use virtual environments. You can look it up, there are plenty of threads explaining on that, as well as the Official documentation.
Related
Right now I'm trying to install python (3.10) and all further installations on my new pc (windows 10) and so far everything is set up:
Python installed
Windows paths for "Python" & "Python\Scrips"
I am able to call the python and pip version and also install some packages. But after installing virtualenv and creating one the - at the moment - unfixable error appears: I am unable to install packages into the pip-path of the virtualenviroment itself. Whenever I'm trying to run any pip-command I'm getting the following error:
Unable to create process using 'C:\Users\ExampleUser\AppData\Local\Programs\Python\Python310\python.exe "C:\folder\env\Scripts\pip.exe" '
As you can see, it's always refering to the original python-path, but on the other hand it's refering to the pip-path of the virtualenv!? Don't know if it's helpful, but when typing in where python and where pip the paths inside the venv are the first one listed. I've also watched out for no blank spaces in my path...
Unfortunately no explanation out there could help me until now and I never faced this problem on my old machine - mostly the same, except some older version of python, pip and virtualenv.
Does anyone else has an idea what I am missing?
downloading Python 3 at the official website and installing it via express installation
Copy & Paste the standalone python into the /python folder and overwriting the python version
running python -m pip install --upgrade pip in cmd
Now pip and python 3 are installed in their latest version.
It's work for me
Could you use venv to create your virtual environment, instead of virtualenv (given that venv is the recommended way to create virtual environments for Python 3.3, and newer)?
If using venv is an option, this procedure may give you some idea on how to do it.
I have not done any Python development on Windows, but I think the basics would be:
python3 -m venv your-env-directory
your-env-directory\Scripts\activate.bat
If using venv is not an option, maybe you can try specifying the -v flag when running your virtualenv command to increase verbosity so you can further troubleshoot what's going on.
try upgrade pip version python -m pip install --upgrade pip
[ Sorry if this answer turns out to be more of a comment than an answer. I only have 21 reputation, so I cannot comment ]
When trying to install pip packages and run python files, is the CWD (Current Working Directory) C:\folder\env\Scripts? If so, try chaning your CWD to C:\folder. I had a similar problem and doing this fixed it.
You may need to look into a cygwin environment, and look into a chroot or jail environment to run the application without conflict.
Have you tried to use virtualenv-wrapper-win module.
It helps me a lot to manage virtual envs
Life is much easier using Anaconda 3 (it's definitely bloated compared to normal Python though), or use the minimal Miniconda (barebone install, basically just Python + a package manager). You can download it here: https://docs.conda.io/en/latest/miniconda.html#windows-installers
Then you can make a new virtual environment super easy:
conda create -n myenv pip
conda activate
If you have multiple environments you do: conda activate [environment_name]
Now you're in your new environment with pip installed. And you get drop down menus in the Windows menu to get to your new environment too, so there isn't any searching required. They just appear. Now if you want to link Jupyter Notebook or Spyder to the installation, it takes more steps since you need more packages. I used this guide which basically activates Jupyter first, then Spyder IDE. https://medium.com/#apremgeorge/using-conda-python-environments-with-spyder-ide-and-jupyter-notebooks-in-windows-4e0a905aaac5
Since you created the environment with pip added you can pip install whatever packages you need. I had to do this recently with OpenBLAS backed NumPy and SciPy (the defaults from pip, not from conda). Now Miniconda is the closest thing to basic Python installation, and comes with some nice tools to make your life easier. Hopefully this is helpful.
I have the following version of python
import sys
print(sys.version)
3.6.5 | packaged by conda-forge | (default, Apr 6 2018, 13:44:09)
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)]
I installed a package with the following command
pip install wfdb
It is succesfully installed because when I then write the command:
pip show wfdb
The following information appears
Location:
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages
However, when I type the command import wfdb in Python notebook or the version of python in terminal, I get the following message
No module named 'wfdb'
Does it have to do with the path on which python is checking where the packages are? How to check this and how to change it?
You have (at least) 2 Python installations, one managed by Anaconda, the other what appears to be an official Python.org Mac build installed system-wide. The pip command on the command-line is the one tied to the Python.org Mac build.
pip is a script that is tied to a specific Python installation, and there can be multiple versions of the script installed in different locations, and is usually also installed with pipX and pipX.Y to match the X.Y version indicator of the Python version it is tied to. For Python 3.6, that means the same script would also be available as pip3 and pip3.6. (This also means that pip can be connected to Python 2 or Python 3, depending on your exact OS setup. It is not a given that pip, without a version number, installs into Python 2.x as some answers may claim).
Note that when you run a command without a path in your shell, (such as pip as opposed to /usr/bin/pip), you are asking your shell to find the command for you in a number of locations, listed in the PATH environment variable. The first location in the PATH list with that command is then fixed. which -a <command> would tell you all possible PATH-registered locations that the command can be found in. You can always use the full path to a command to bypass the PATH search path.
You can always verify what Python version the pip command is connected to with:
pip -V
which will output the version of pip and the location it is installed with. It'll print something like
pip pipX.pipY path/to/pythonX.Y/site-packages/pip (python X.Y)
where pipX.pipY is the pip version number and path/to/pythonX.Y tells you what Python installation this is for.
You can try to match this with the Python version by running
python -m site
which outputs the Python module search path for that Python version. Python can be run with python, pythonX and pythonX.Y too, and is subject to the same PATH search.
Note the -m switch there, that instructs Python to find a module in it's module search path and execute it as a script. Loads of modules support being run that way, including pip. This is important as that helps avoid having to search for a better pip command if you already can start the right Python version.
You have several good options here:
Since you are using Anaconda, you could look for a conda package for the same project. There is such a package for wfdb. Install it with
conda install wfdb
Anaconda aims to give you a wider software management experience that includes a broader set of software options than just the Python PyPI ecosystem, and conda packages usually manage more things than just the Python package.
Conda packages are usually maintained by a different set of developers from the package itself, so there may be a newer version available on PyPI (requiring pip install) than there is on Conda.
This is not an option for all Python packages, if there is no conda package you have to use pip. See Installing non-conda packages.
you can use the conda command to create a conda environment. Once you have an environment created, you can activate it with
source activate <name_of_cenv>
to alter your PATH settings. With the envirnoment 'active' the first directory listed on your PATH is the one for the conda environment and the pip command will be the one tied to that environment.
Note that a conda environment gives you an isolated environment for a specific project, keeping the library installation separate from the rest of your Python packages in the central site-packages location. If you want to install a package for all of your Anaconda Python projects, don't use a conda environment.
Use the Anaconda Python binary to run pip as a module; when you can run /path/to/python or pythoncommand to open the right Python version, you can use that same path to run /path/to/python -m pip ... instead of pip ... to be absolutely certain you are installing into the correct Python version.
Look for a better pip command, with which -a pip or which -a pip3.6, etc. But if you already know the Python binary, look in the same bin location for pip. If you have anaconda/bin/python, then there probably is a anaconda/bin/pip too.
As you can read here:
pip3 and pip would make a difference only when you are not using any
environment managers like virualenv (or) conda. Now as you are
creating a conda environment which has python==3.x, pip would be
equivalent to pip3.
For this reason it could be you did not activate your Conda environment before installing required packages and running your code.
Activate the new environment:
On Windows:
activate myenv
On macOS (this should be your option) and Linux:
source activate myenv
NOTE: Replace myenv with the name of the environment.
which python
gives the you the PATH to python
and then /path/to/python -m pip install thepackagetobeinstalled
Many thanks #MartijnPieters
You have installed python2.x package and you're using python3.x. Try:
pip3 install wfdb
If you don't have pip3 run:
[apt-get/yum] install python3-pip
You can see what packages you have currently installed by running:
pip freeze
and for python 3.x packages
pip3 freeze
Please remember each time you install a Python package, it will be placed in the directory for one particular Python version. Hence your error.
I went ahead and downloaded the latest version of python3 onto my mac from python.org/downloads/, however, I was having trouble using pip in my terminal, so I used Homebrew to install python via the command line. It looks like Homebrew installed a 2.x version. I also know that my mac already has some python2.x version built in. I would like to remove the 2.x versions and only use the python3.6.1 that I have. How can I accomplish this?
There are several aspects to your question: invoking different major Python versions, removing unneeded Homebrew-installed packages, and identifying which installation is in use.
Major Python versions, 2 and 3, use different command names to invoke them. The first, python, uses the system default according to your configured PATH environment variable and should default to Python 2, but does not on all systems. Reference: https://www.python.org/dev/peps/pep-0394/
Instead, explicitly invoke the version you want, e.g. by running python3. Note that virtual environments (created by running python3 -m venv <name> or virtualenv) will create an isolated environment using the Python version of your choice where python will always use that version, and pip will install packages relative to, instead of system-wide, which may avoid the requirement of superuser (sudo) privileges.
Note that Homebrew might not override the default versions provided by the system, requiring you to make changes to your PATH to force Homebrew's versions to be preferred. After installing a package Homebrew will inform you of this type of information, and you can get the messages later by running: brew info <package>
Uninstalling a brew-installed package requires running: brew uninstall <package>
For more information, run: brew help
As mentioned above, identifying just which Python you're using starts with the PATH. To quickly identify the executable you invoke when typing python, python2, or python3 into your shell is by running: which python — this can help identify if you're using the Homebrew installed version or the system version, or if you are using a version from an active virtual environment. You can also use which to identify the pip or pip3 command location.
This gets you the first part of the equation. The second then boils down to: where does Python think things are? Invoking it then running the following will tell you exactly where it thinks things (imports) are:
import sys, print
pprint(sys.path)
This can help track down issues related to why you can't import that package you just installed with pip.
I can highly recommend using a virtual environment to isolate your projects from system level packages and differences. Within one, python and pip will basically always behave as expected, as you determined when creating the environment.
What is a way to instaill python modules within cygwin? I'm new to cygwin and couldn't find pip or anything like that in the setup.exe package. I've looked around and I can't find a definitive way to do it. Does anyone have advice?
On windows, under cygwin follow the below steps.
1.Ensure python is installed in cygwin. Type python on the terminal of cygwin and it should launch the python shell. If it doesn't launch the setup file for cygwin and select python from the package list and install.
2. Now, install pip if it's not already installed. Provide full path if you have multiple python installations e.g.
/usr/bin/python2.7 -m ensurepip
/usr/bin/python3.6 -m ensurepip
3. Now, you can use pip to install the python package. Depending upon the installation in which you want the package to be installed, run below command(s)
/usr/bin/python2.7 -m pip install pyyaml
/usr/bin/python3.6 -m pip install pyyaml
In standard python installation, pip like scripts goes under "your_python_directory\Scripts". (in my system C:\Python34\Scripts) Make sure you have added this path to system directories (Environment Variables). Then
pip.exe install my_package_name
will work fine.
Also for configuring within cygwin this will help.
PS: sorry for confusion though I thought you meant you have installed python separately from cygwin. I believe this thread answers your question.
I would suggest installing the python in windows.
Suppose you install the python in D drive, then just call the installed python from cygwin like
/cygdrive/d/Python37/python.exe
In this case, you would not get two versions of python (one in cygwin, one in windows). And you can call the python from other terminals as well.
I went thought and installed pip and then added a bunch of libraries that I like to use and then, only after installing everything, did I realize that everything went into the 2.7.2 sit-packages directory, so the Python2.7.5 version doesn't see anything.
Now, If I type python --version in the terminal, the correct version is started. However, pip is still "tied" to the default version of Python.
How do I go about telling OSX to look at the new version of Python for everything?
Honestly, one way around this is to make sure that virtualenv works with the right version, and just use pip inside the virtualenv.
A common pattern of Python installation on the mac is to use Home Brew which is a package manager for the mac. You can then install python using:
sudo brew update
brew install python
Provided you have the XCode command line tools already installed.
After I think that the Home Brew Python will be the first in the path. If this is not the case, it might be simpler to use a virtualenv by installing the package with the pip provided by the Mac Brew install (/usr/local/Cellar/python/2.7.5/bin/pip).
After this is done you need to create a virtualenv
virtualenv ~/path/to/the/env
and to activate it
source ~/path/to/the/env/bin/activate
This will be a brand new python and your path will be configured correctly (the python and the pip will be the right ones). You can always delete it, deactivate it or source it as needed.