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pip cannot uninstall <package>: "It is a distutils installed project"

I tried to install the Twilio module:
sudo -H pip install twilio
And I got this error:
Installing collected packages: pyOpenSSL
Found existing installation: pyOpenSSL 0.13.1
Cannot uninstall 'pyOpenSSL'. It is a distutils installed project and
thus we cannot accurately determine which files belong to it which
would lead to only a partial uninstall.
Anyone know how to uninstall pyOpenSSL?

This error means that this package's metadata doesn't include a list of files that belong to it. Most probably, you have installed this package via your OS' package manager, so you need to use that rather than pip to update or remove it, too.
See e.g. Upgrading to pip 10: It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall. · Issue #5247 · pypa/pip for one such example where the package was installed with apt.
Alternatively, depending on your needs, it may be more productive to not use your system Python and/or its global environment but create a private Python installation and/or environment. There are many options here including virtualenv, venv, pyenv, pipenv and installing Python from source into
/usr/local or $HOME/$HOME/.local (or /opt/<whatever>).
Finally, I must comment on the often-suggested (e.g. at pip 10 and apt: how to avoid "Cannot uninstall X" errors for distutils packages) --ignore-installed pip switch.
It may work (potentially for a long enough time for your business needs), but may just as well break things on the system in unpredictable ways. One thing is sure: it makes the system's configuration unsupported and thus unmaintainable -- because you have essentially overwritten files from your distribution with some other arbitrary stuff. E.g.:
If the new files are binary incompatible with the old ones, other software from the distribution built to link against the originals will segfault or otherwise malfunction.
If the new version has a different set of files, you'll end up with a mix of old and new files which may break dependent software as well as the package itself.
If you change the package with your OS' package manager later, it will overwrite pip-installed files, with similarly unpredictable results.
If there are things like configuration files, differences in them between the versions can also lead to all sorts of breakage.

I had the same error and was able to resolve using the following steps:
pip install --ignore-installed pyOpenSSL
This will install the package with latest version and then if you try to install,
pip install twilio
It will work.

Generally, for similar errors, use this format:
pip install --ignore-installed [package name]==[package version]

I just had this error and the only way I was able to resolve it was by manually deleting the offending directory from site-packages.
After doing this you may need to reinstall the packages with --force-reinstall.

Reading the above comments, I understood that package a was installed with conda and the new package b that I was trying to install using pip was causing problems. I was lucky that package b had conda support so using conda to install package b solved the problem.

In my case, I was installing a package from internal git using the following command:
python -m pip install package.whl --force
I was doing this because I didn't want to explicitly uninstall the previous version and just replace it with a newer version. But what it also does is install all the dependencies again. I was getting the error in one of those packages. Removing --force fixed the problem.
I want to add, having --ignore-installed also worked for me. And removing --force is essentially doing the same thing in my case.

How to install Yaml and some other Python modules on OS X sierra? [duplicate]

I'm having a hard time setting up python packages. EasyInstall from SetupTools is supposed to help that, but they don't have an executable for Python 2.6.
For instance to install Mechanize, I'm just supposed to put the Mechanize folder in C:\Python24\Lib\site-packages according to INSTALL.txt, but runnning the tests does not work. Can someone help shed some light on this? Thanks!

The accepted answer is outdated. So first, pip is preferred over easy_install, (Why use pip over easy_install?). Then follow these steps to install pip on Windows, it's quite easy.
Install setuptools:
curl https://bootstrap.pypa.io/ez_setup.py | python
Install pip:
curl https://bootstrap.pypa.io/get-pip.py | python
Optionally, you can add the path to your environment so that you can use pip anywhere. It's somewhere like C:\Python33\Scripts.

Newer versions of Python for Windows come with the pip package manager. (source)
pip is already installed if you're using Python 2 >=2.7.9 or Python 3 >=3.4
Use that to install packages:
cd C:\Python\Scripts\
pip.exe install <package-name>
So in your case it'd be:
pip.exe install mechanize

This is a good tutorial on how to get easy_install on windows. The short answer: add C:\Python26\Scripts (or whatever python you have installed) to your PATH.

You don't need the executable for setuptools.
You can download the source code, unpack it, traverse to the downloaded directory and run python setup.py install in the command prompt

Starting with Python 2.7, pip is included by default. Simply download your desired package via
python -m pip install [package-name]

As I wrote elsewhere
Packaging in Python is dire. The root cause is that the language ships without a package manager.
Fortunately, there is one package manager for Python, called Pip. Pip is inspired by Ruby's Gem, but lacks some features. Ironically, Pip itself is complicated to install. Installation on the popular 64-bit Windows demands building and installing two packages from source. This is a big ask for anyone new to programming.
So the right thing to do is to install pip. However if you can't be bothered, Christoph Gohlke provides binaries for popular Python packages for all Windows platforms http://www.lfd.uci.edu/~gohlke/pythonlibs/
In fact, building some Python packages requires a C compiler (eg. mingw32) and library headers for the dependencies. This can be a nightmare on Windows, so remember the name Christoph Gohlke.

I had problems in installing packages on Windows. Found the solution. It works in Windows7+. Mainly anything with Windows Powershell should be able to make it work. This can help you get started with it.
Firstly, you'll need to add python installation to your PATH variable. This should help.
You need to download the package in zip format that you are trying to install and unzip it. If it is some odd zip format use 7Zip and it should be extracted.
Navigate to the directory extracted with setup.py using Windows Powershell (Use link for it if you have problems)
Run the command python setup.py install
That worked for me when nothing else was making any sense. I use Python 2.7 but the documentation suggests that same would work for Python 3.x also.

Upgrade the pip via command prompt ( Python Directory )
D:\Python 3.7.2>python -m pip install --upgrade pip
Now you can install the required Module
D:\Python 3.7.2>python -m pip install <<yourModuleName>>

pip is the package installer for python, update it first, then download what you need
python -m pip install --upgrade pip
Then:
python -m pip install <package_name>

You can also just download and run ez_setup.py, though the SetupTools documentation no longer suggests this. Worked fine for me as recently as 2 weeks ago.

PS D:\simcut> C:\Python27\Scripts\pip.exe install networkx
Collecting networkx
c:\python27\lib\site-packages\pip\_vendor\requests\packages\urllib3\util\ssl_.py:318: SNIMissingWarning: An HTTPS reques
t has been made, but the SNI (Subject Name Indication) extension to TLS is not available on this platform. This may caus
e the server to present an incorrect TLS certificate, which can cause validation failures. You can upgrade to a newer ve
rsion of Python to solve this. For more information, see https://urllib3.readthedocs.io/en/latest/security.html#snimissi
ngwarning.
SNIMissingWarning
c:\python27\lib\site-packages\pip\_vendor\requests\packages\urllib3\util\ssl_.py:122: InsecurePlatformWarning: A true SS
LContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL con
nections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.
readthedocs.io/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
Downloading networkx-1.11-py2.py3-none-any.whl (1.3MB)
100% |################################| 1.3MB 664kB/s
Collecting decorator>=3.4.0 (from networkx)
Downloading decorator-4.0.11-py2.py3-none-any.whl
Installing collected packages: decorator, networkx
Successfully installed decorator-4.0.11 networkx-1.11
c:\python27\lib\site-packages\pip\_vendor\requests\packages\urllib3\util\ssl_.py:122: InsecurePlatformWarning: A true SSLContext object i
s not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade
to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.io/en/latest/security.html#insecureplat
formwarning.
InsecurePlatformWarning
Or just put the directory to your pip executable in your system path.

As mentioned by Blauhirn after 2.7 pip is preinstalled. If it is not working for you it might need to be added to path.
However if you run Windows 10 you no longer have to open a terminal to install a module. The same goes for opening Python as well.
You can type directly into the search menu pip install mechanize, select command and it will install:
If anything goes wrong however it may close before you can read the error but still it's a useful shortcut.

Force pip to skip or ignore bad hash on download cache

Wondering if anyone knows a workaround to force pip to either completely skip hash checks or ignore bad sums when installing from a download cache? Install cmd is:
pip.exe install --target=C:\WHERE_I_WANT_INSTALLED --download-cache=C:\MY_DL_CACHE mitmproxy
Mitmproxy requires a specific version of pillow, and in that specific version there just happens to be a defined C function whos signature collides with another function in an include within Mingw x86_64. I'm not changing out my toolchain, as anyone who uses mingw on windows knows, it's a disgustingly painful process to find and keep a stable version.
Anyway, I've posted the question as a bug report on pips github but I thought I'd pose the question here. Thanks in advance.

Well, I found the answer in the very last place I would ever think to look: the documentation.
So basically you run a few commands to have pip download everything that is required for what you're trying to install. In this case, its was mitmproxy. So first I grabbed the requirements.txt file for mitmproxy, and dropped it into a dir. Commands to download packages were:
pip install --download C:\MY_SECRET_PATH\mitm\dl-cache six
pip install --download C:\MY_SECRET_PATH\mitm\dl-cache mock
pip install --download C:\MY_SECRET_PATH\mitm\dl-cache itsdangerous
pip install --download C:\MY_SECRET_PATH\mitm\dl-cache cryptography
pip install --download C:\MY_SECRET_PATH\mitm\dl-cache mitmproxy
Now, everything required for mitm-proxy is stored in the provided path. We then supply this path and a couple of other flags to the command for installing what we're after, again mitmproxy. To make things more interesting, I'm installing all of this stuff in a custom dir. So that command is as follows:
pip.exe install mitmproxy --no-index --target=C:\MY_SECRET_PATH\mitm --find-links=C:\MY_SECRET_PATH\mitm
So we're basically telling pip to install the selected package and all its deps offline, not checking pypy and therefore skipping hash checks. You're then obviously free to modify the sources of the packages you've downloaded, as I have.

Trouble installing scipy despite having python2.7 and numpy installed already

I'm having trouble installing scipy via the binaries provided at http://sourceforge.net/projects/scipy/files/scipy/
Double clicking on the mpkg file after mounting the dmg installer gives the following error:
"scipy 0.13.0 can't be installed on this disk. scipy requires System Python 2.7 to install"
However, I already have python 2.7 and numpy installed. The python 2.7 came default with OSX Lion, so I assume it is System Python. With other python modules, one normally can download the binary then run
python setup.py install
Is there a way to cd through the mpkg file and locate a setup.py? Any advice install via this dmg installer?
I know there are other ways to manage python modules, like port and brew. However, I already installed a bunch of packages through setup.py, and I couldn't figure out how to get port to recognize those packages (for example, it will try to reinstall python and numpy via port)
Thanks!

If you have Mavericks and XCode 5, then you'll have to install Command Line Tools manually from the Apple Developer Site. I found this helpful post

You've got a few misconceptions here.
With other python modules, one normally can download the binary then run python setup.py install
No, that's what you do with source packages.
Is there a way to cd through the mpkg file and locate a setup.py?
No. What's inside an mpkg are pkg files. Which are filled with xar archives filled with cpio archives. Inside there is the built version of SciPy—that is, the files that setup.py would have copied to your site-packages if you'd run it—not the source package.
But you can download the source package yourself.
Or, better, let pip (or easy_install, but pip is better) download and run the setup.py for you.
Any advice install via this dmg installer?
If it won't work, my advice would be to not use it, and instead install with pip.
This blog post explains it, but I'll give you the details relevant to you below.
I know there are other ways to manage python modules, like port and brew. However, I already installed a bunch of packages through setup.py, and I couldn't figure out how to get port to recognize those packages.
You can't. MacPorts will not touch your system Python; it builds its own separate Python 2.7, with a completely independent site-packages directory and everything else. You would have to reinstall everything for this second Python 2.7. And deal with the confusion of having two Python 2.7 installations on the same machine.
Don't do that unless you absolutely have to.
In fact, if you want to use Homebrew for anything (and you do, see below), uninstall MacPorts, unless you really need it for something.
So, here are the steps:
Uninstall MacPorts.
I assume you already have Xcode and its Command Line Tools.
I assume you already have Homebrew.
Install a Fortran compiler with brew install gfortran.
Lion's Python 2.7 comes with easy_install, but not pip. So sudo easy_install pip to fix that. While you're at it, I'd suggest sudo easy_install readline, because you'll want that for ipython, and it won't work right with pip.
Apple's pre-installed NumPy has to be upgraded, and rebuilt with Fortran support, to make SciPy work. Fix that with sudo pip install --upgrade --force-reinstall numpy.
If you want ipython, pandas, etc. sudo pip install each of them as well.
In case you're considering upgrading soon, the exact same steps worked for me with OS X 10.9.0, except for some extra work to get the Xcode 5 command line tools set up.

How to install pip in a new python installation

I recently installed python 2.7.2 on my Mac running OSX 10.6.8. Previously, I had version 2.6. I set my path in .bash_profile as follows:
export PATH=/usr/local/bin:$PATH
export PATH=/usr/local/share/python:$PATH
so that when I run python it will refer to my new installation. It does.
I would also like to use pip with my new installation, but the problem is that I already have the current version of pip installed at
/usr/local/bin/pip.
I tried to re-install pip with:
easy_install pip
But, of course this does not put pip in the desired new directory
/usr/local/share/python/pip
but simply refers to the existing version in /usr/local/bin/pip.
Can someone tell me how to fix this?
I would like to then use pip to install NumPy and SciPy in the correct directory (I was having trouble getting the SciPy installation to work with my old version of python, hence the new install).
If you'd like, you can visit the website where I found instructions for installing python 2.7, creating/updating my .bash_profile, installing pip, and NumPy and SciPy. Might provide some insight, or I'm happy to give more details if needed. Thanks!
http://www.thisisthegreenroom.com/2011/installing-python-numpy-scipy-matplotlib-and-ipython-on-lion/#python

Install distribute as per the instructions at http://pypi.python.org/pypi/distribute .
Make sure you specify the full path to the python executable (/usr/local/share/python/python or smth in your case).
$ curl -O https://svn.apache.org/repos/asf/oodt/tools/oodtsite.publisher/trunk/distribute_setup.py
$ /usr/local/share/python/python distribute_setup.py
Then you should have /usr/local/share/python/easy_install.
After that, run:
$ /usr/local/share/python/easy_install pip
Then you should have /usr/local/share/python/pip.
Depending on the ordering of things in your PATH, either your old, or the newly installed pip is executed when you execute the pip command, so you either might have to adapt your PATH, or specify the full path to /usr/local/share/python/pip when installing eggs.
(shameless plug:
In any case, you might consider using virtualenv for installing packages into a "project" specific isolated environment, as opposed to installing them globally.)

I needed to uninstall brew's python.
Then, I was left with python v2.7.6
Next to install, pip I ran
sudo easy_install pip
installed fine and working

I had a similar issue, try this:
$ python -m pip install --upgrade --force-reinstall pip
This will force reinstall pip with whatever version of python you use including installing the binary.

A few days ago I had a friend who was starting Python Programming and needed help with the same issue: installing pip. There are debates over which one to choose between easy_install and pip and it seems everybody is heading the pip direction. Either way, installing either of them can be frustrating.
You can use this simple tutorial : installing pip package manager the easy way
Here are what you should keep in mind as you follow the above guide:
If you already have an older version installed, uninstall it or totally remove the python installation
Once that is cleared, download an install Python.
After that, download ez_setup.py file and save it to your desktop - easily accessible from the command line
Now run it from the command line and it will install easy_install for you after which,
You can use it to install pip.
Once again, you can do this or use the above link to find a simple step-by-step guide on how to get it installed on your computer.
Good luck.

Just so that people knew, ATM we can install PIP by downloading get-pip.py from the page with docs and run it like this:
c:\python27\python.exe get-pip.py
BTW, Python 3.4 comes with PIP pre-installed.

One of the command line options lets you choose where to install to.
--install-dir (-d) install package to DIR
So something like - # easy_install pip -d /usr/local/share/python
(Please correct me if I'm wrong.)

Just wanted to say that I found a way to get around my problem. I don't know that I can explain it perfectly, since I am not very good at understanding what I am doing with this stuff just yet! But, the problem seems to have been with my PATH. I removed the PATH that I posted in my original question, and then used easy_install pip. It went straight to python 2.7.2 (my new version) with no problem. I then successfully used pip to install NumPy and SciPy in the correct location, and they both work. Thanks to ErikAllik and FakeRainBrigand for taking the time to look into it!