Develop Reference

How do I install python third party libs on the m1 chip?

The Mac Book Air M1 chip doesn't seem to support pep517 according to the errors of installing third-party libraries with pip or brew. Even using these methods without pep517 downloading the library locally didn't work. How does one circumvent this?
Error from using pip install pandas:
Failed to build numpy
ERROR: Could not build wheels for numpy which use PEP 517 and cannot be installed directly
I've tried this:
pip install <lib>
installing the library locally and trying to install with pip without pep517
brew install <lib>
openblas installation of lib
python env on the intel venv

I had the exact same problem, with a different library but with the same error code for PEP 517, I was using python 3.9 at the time, I checked the docs and found out that it's a problem with the python version for the library, downgraded to Python 3.6 and voila! it worked.
Basically try downgrading to Python 3.6 and check.

Installing python libraries through Anaconda seems to work. I simply downloaded the installer and could later use the libraries globally. If someone has a better in-depth explanation, feel free to comment.

I was having the same message when trying to install a different package. I solved by removing the CommandLineTools and installing it again. The steps were:
sudo rm -r /Library/Developer/CommandLineTools
wait for command prompt...
xcode-select --install
This solved the issue for me.

Installing numpy for Python 2.7 while also having Python 3.4 installed?

I have both Python 2.7 and Python 3.4 (and have to have both because for the class I'm running, students have the option of using either). One student has used Python 2.7 and numpy for their project, but when I attempt to install numpy, it installs it to 3.4. I need to install it to 2.7.
I'm using numpy 1.9 from this site, which I'm told is also 2.7-specific: http://sourceforge.net/projects/numpy/files/NumPy/
However, nonetheless it still goes to the 3.4 folder. Copying it to Python 2.7 didn't work, obviously.
How do I do this?

I recommend installing with pip.
pip install numpy
If this doesn't work on windows then download the binary from http://www.lfd.uci.edu/~gohlke/pythonlibs/ and convert it to a wheel before installing.
pip install wheel
wheel convert path/to/binary
pip install numpy_wheel
Pip is recommended because you can uninstall.
To check where you are installing to
pip -V
You may have an environmental variable path to the wrong pip.

Assuming that you are using, or at least you should use pip to install the library. You can specify the python version to be installed by changing the suffix, e.g. pip-2.7 install numpy.
pip install numpy
pip-2.7 install numpy
pip-3.4 install numpy
As an alternative, in case that you do not want to use pip is to download and install the library using setup with a similar technique.
python setup.py install
python2.7 setup.py install
python3.4 setup.py install

Your PATH isn't setup correctly.
C:> where pip
Should tell you which pip it is trying to use, and it is likely whichever one it found on your PATH first...
So, instead, you will want to run it as
C:> C:\mypython2install\pip.exe install numpy
Or, setup your path correctly. See here

Just one other note on issues like this. I had a similar problem with Python 2.7 libraries not being found, because I had miniconda installed for a Python virtual environment that was hijacking calls to python from other programs. After deleting the minconda directory in my home the problem went away and python libraries that were properly installed were found again.

Note-This answer is particularly for Windows PC which has both Python2 & Pyhton3 installed on it.
Both the versions of Python has their different directories somewhat like
"C:\Python27\" ----for python2
"C:\Python35\" ---- for python3
*(or it depends on what path you chose while installing Python**)*
pip GENERALLY exist under the directory "C:\Python**\Scripts"
there you can find exe files like:
pip.exe/pip2.exe/pip2.7.exe ----for python2
pip3.exe/pip3.5.exe ----for python3
to install packages on python2:
use
Python27\Scripts\pip2.exe install package_name
(where the 1st argument is the path of exe file, it might differ for your system)
to install packages on python3:
use
Python35\Scripts\pip3.exe install package_name
there is no need to uninstall any version of python to achieve the task.

Macports does not recognize pip-installed packages

Until today, I have been using the macports version of python27 and installing python packages through macports. Today, I needed some packages which were not available through macports; I learned about pip and found them there. After installing these packages through pip, however, I realized that neither pip nor macports could see what had been installed by the other. So, for consistency, I decided to uninstall all macports packages, install python27 and py27-pip through macports and then proceed to install all of my python packages through pip.
This worked fine, but since macports does not know about my pip-installed python packages, I ran into trouble when installing something else which depends on python (e.g., inkscape): macports tried to install its own version of, e.g. py27-numpy (already installed by pip) and then failed installation because it "already exists and does not belong to a registered port."
Is there a consistent way to use pip and to get macports to recognize that the python packages it might need for something else are already installed?

The solution is: dont use Macports for installing Python's packages.
Macports is a general package manager and it registers installed packages in its database.
Pip is a package manager for Python so if you want to install Python package, use appropriate package management tool. Pip doesnt have it's own database to keep evidence about installed stuff - it just checks Python's path to see if the package is there (and that's what you want).
Sooner or later you'll use Virtualenv anyway and you'll need pip to install packages in there too so it's better to use it everywhere.

Installing Python eggs under PyPy

How do I install Python egg under PyPy?
During installation, PyPy created /usr/lib64/pypy-1.5/site-packages/ directory. So, I tried using easy_install with prefix set to this directory, however it complains that this is not a valid directory for eggs. Do I just copy eggs from /usr/lib/python2.7/site-packages, or is it as easy as using easy_install (with some changes in configuration, perhaps)?
My working environment is Fedora 15 Beta, Python 2.7.1 (/usr/bin/python), PyPy 1.5.0-alpha0 with GCC 4.6.0 (in /usr/bin/pypy, installed from RPM using yum), easy_install version is: distribute 0.6.14 (usr/bin/easy_install).

First, you need to make sure that you have distribute installed specifically for PyPy. I don't know how fedora packages things, but in general installing a package for cpython does not make it available also for PyPy. In particular, /usr/bin/easy_install is probably CPython-only.
If you use a "normal" install of PyPy, you have this directory structure:
/opt/pypy-1.5/
bin/
site-packages/
lib-python/
lib_pypy/
Then you can download http://python-distribute.org/distribute_setup.py and execute it:
$ /opt/pypy-1.5/bin/pypy distribute_setup.py
Now, you should have /opt/pypy-1.5/bin/easy_install, which will install packages inside /opt/pypy-1.5/site-packages.
However, I have no clue how pypy is packaged in fedora. It it's "just" installed in /usr/bin, then there are chances that installing distribute will overwrite the original cpython's /usr/bin/easy_install.

What is causing ImportError: No module named pkg_resources after upgrade of Python on os X?

I just updated Python to 2.6.4 on my Mac.
I installed from the dmg package.
The binary did not seem to correctly set my Python path, so I added '/usr/local/lib/python2.6/site-packages' in .bash_profile
>>> pprint.pprint(sys.path)
['',
'/Users/Bryan/work/django-trunk',
'/usr/local/lib/python2.6/site-packages',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python26.zip',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-darwin',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac/lib-scriptpackages',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-tk',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-old',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-dynload',
'/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages']
Apparently that is not all the required paths because I can't run iPython.
$ ipython
Traceback (most recent call last):
File "/usr/local/bin/ipython", line 5, in <module>
from pkg_resources import load_entry_point
ImportError: No module named `pkg_resources`
I've done Google searches and I can't really figure out how to install pkg_resources or make sure it's on the path.
What do I need to do to fix this?

I encountered the same ImportError. Somehow the setuptools package had been deleted in my Python environment.
To fix the issue, run the setup script for setuptools:
curl https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py | python
If you have any version of distribute, or any setuptools below 0.6, you will have to uninstall it first.*
See Installation Instructions for further details.
* If you already have a working distribute, upgrading it to the "compatibility wrapper" that switches you over to setuptools is easier. But if things are already broken, don't try that.

[UPDATE] TL;DR pkg_resources is provided by either Distribute or setuptools.
[UPDATE 2] As announced at PyCon 2013, the Distribute and setuptools projects have re-merged. Distribute is now deprecated and you should just use the new current setuptools. Try this:
curl -O https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py
python ez_setup.py
Or, better, use a current pip as the high level interface and which will use setuptools under the covers.
[Longer answer for OP's specific problem]:
You don't say in your question but I'm assuming you upgraded from the Apple-supplied Python (2.5 on 10.5 or 2.6.1 on 10.6) or that you upgraded from a python.org Python 2.5. In any of those cases, the important point is that each Python instance has its own library, including its own site-packages library, which is where additional packages are installed. (And none of them use /usr/local/lib by default, by the way.) That means you'll need to install those additional packages you need for your new python 2.6. The easiest way to do this is to first ensure that the new python2.6 appears first on your search $PATH (that is, typing python2.6 invokes it as expected); the python2.6 installer should have modified your .bash_profile to put its framework bin directory at the front of $PATH. Then install easy_install using setuptools following the instructions there. The pkg_resources module is also automatically installed by this step.
Then use the newly-installed version of easy_install (or pip) to install ipython.
easy_install ipython
or
pip install ipython
It should automatically get installed to the correct site-packages location for that python instance and you should be good to go.

In case of upgrading your python on mac os 10.7 and pkg_resources doesn't work, the simplest way to fix this is just reinstall setuptools as Ned mentioned above.
sudo pip install setuptools --upgrade
or sudo easy_install install setuptools --upgrade

On my system (OSX 10.6) that package is at
/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/pkg_resources.py
I hope that helps you figure out if it's missing or just not on your path.

The reason might be because the IPython module is not in your PYTHONPATH.
If you donwload IPython and then do
python setup.py install
The setup doesn't add the module IPython to your python path.
You might want to add it to your PYTHONPATH manually. It should work after you do :
export PYTHONPATH=/pathtoIPython:$PYTHONPATH
Add this line in your .bashrc or .profile to make it permanent.

I realize this is not related to OSX, but on an embedded system (Beagle Bone Angstrom) I had the exact same error message. Installing the following ipk packages solved it.
opkg install python-setuptools
opkg install python-pip

I got this error on Ubuntu, and the following worked for me:
Removed the dropbox binaries and download them again, by running:
sudo rm -rf /var/lib/dropbox/.dropbox-dist
dropbox start -i

I encountered with the same problem when i am working on autobahn related project.
1) So I download the setuptools.-0.9.8.tar.gz form https://pypi.python.org/packages/source/s/setuptools/ and extract it.
2 )Then i get the pkg_resources module and copy it to the folder where it needed.
**in my case that folder was C:\Python27\Lib\site-packages\autobahn

In my case, package python-pygments was missed. You can fix it by command:
sudo apt-get install python-pygments
If there is problem with pandoc. You should install pandoc and pandoc-citeproc.
sudo apt-get install pandoc pandoc-citeproc

Try this only if you are ok with uninstalling python.
I uninstalled python using
brew uninstall python
then later installed using
brew install python
then it worked!