Python site-packages and corresponding interpreter - python-2.7

I used brew to install python 2.7 and 3.5 on Mac. SOMEHOW I have this site-packages directory /usr/local/lib/python2.7/site-packages.
But every python interpreter on the system points to every other site-packages directory EXCEPT this one. How do I use THIS site-packages directory?
(This is all because I need Vips. I'd installed this before, but now I'm using a different machine and I can't figure out how on Earth I got it to work before.)

The vips docs have a checklist and an explanation of what happens when Python tried to import vips:
http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/using-from-python.html
But briefly you need to:
You have several Pythons installed, make sure you are invoking the brew one.
Make sure that that Python has a gi repository containing the Vips.py overrides.
Make sure you have a Vips-8.0.typelib file in /usr/local/lib/lib/girepository-1.0/.

SOLVED.
I didn't want to have to resort to resetting my dev box to factory settings, but I did. I hope this helps somebody...
If Python already exists on your system, and you're planning on installing Python yourself or with Homebrew (because you only get python2.7 out of the box), make sure you install the new Python first. Then put the install location first in your PATH. Then install your modules. In that order. I knew something was wrong, so I uninstalled Python/3 and Vips. But when I reinstalled them, for whatever reason Vips still didn't know to bind itself to the Python in /usr/local/Cellar. Even though I had /usr/local/Cellar first in PATH.
So to recap -- first install Homebrew, then set the PATH, then install python/python3, and finally install Vips. And you're good to go.

Related

New point of view: pip dealing with multiple Python versions, Canopy, Anaconda on Linux

Using pip with different Python version is a common problem, as I see when I search the Internet. There are a lot of answers around, also in this forum. However nobody seems to encounter the same problem that I have:
I use Canopy python most and it was installed first. Later I installed Anaconda. Now when I try to install a program with pip it always install it in Canopy (or refuse to install it because it is already installed in Canopy.
for example:
$ pip install ipython
gives:
Requirement already satisfied...
but there are no ipython in my Anaconda-folder, it is in the /Enthought/Canopy_64bit/... folder
How can I overcome this problem?
Both versions are 2.7 and even if one is 2.7.11 and the other 2.7.12, it did not work to distinguish between the two by this.
Maybe you can try the following.
Find where both pip-s reside (whereis pip, I have it on ~/anaconda2/bin), then cd to the pip directory of the python version you want, and execute it from there.
I manage with the help of J. Corson comment:
When you want to use a particular Python installation, activate the desired environment. In my chase
source /home/per/anaconda_ete/bin/activate
then using pip made the installation in the anaconda python and I could install ipython and other stuff there... fine, thanks!

how to revert make install and use make altinstall

i had followed this tutorial in other to overwrite python2.7 with python 3.4.4 and it worked very nice. Only one thing was wrong. typing python, still goes to python2.7 and python3 goes to python3.4.4. so from what i learnt is that
It is critical that you use make altinstall when you install your custom version of Python. If you use the normal make install you will end up with two different versions of Python in the filesystem both named python. This can lead to problems that are very hard to diagnose.
Please help me revert this.
went through this blog Install Python on Linux (Centos).
I had to re-run make altinstall with sudo command of course. I tried this after that
`sudo ln -s /usr/local/bin/python3.4 /usr/local/bin/python`.
which have me
ln: creating symbolic link `/usr/local/bin/python': File exists
I had to delete the path /usr/local/bin/python.
and then tried again.
problem solved

Python (Win 10): Installing matplotlib requires packages "freetype" and "png"?

I've been trying to install Python's matplotlib library for use with PyPlot, for use with Julia. I managed to get everything in place except for this one final library, and I feel as though I've hit a deadend trying to get it working.
When trying to install matplotlib (I've attempted using pip, regular python install, and easy_install), I get the following message at the very end of the install output, after which it is NOT installed:
* The following required packages can not be built:
* freetype, png
Confused about this, I looked around online and installed both of these (at least, what I think these were). One was the freetype project, and the other was LibPng, which was the closest thing I could find to a "png package" for windows or python in general.
This didn't initially work (for either of them), and I read somewhere that I needed a freetype.dll in my system32 folder. It was a long shot, but I went to where I installed freetype and pulled out the dll and renamed it, placing it in system32. This of course did not work (again, long shot).
Anyway, that's where I'm at. No idea where to go from here, and I'm unsure if I even grabbed the correct "packages" I should be using. Thoughts?
Use a more powerful installer
I would recommend to use Anaconda or Miniconda. In my experience with many Windows users, this is the simplest way to install packages such as matplotlib.
Anaconda
Anaconda comes with many packages for scientists. Matplotlib works out of the box. Just install as user not root.
Minoconda
If you don't want all packages of Ananconda use Miniconda
Conda
Both ways of installation (Anaconda or Miniconda) provide conda. It is an improved pip/virtualenv.
You can install matplotilb with this command:
conda install matplotlib
Enviroments:
You can create a new environment and install the packages you like:
conda create -n my_project35 python=3.5
activate my_project35
conda install matplotlib
or
conda create -n my_project27 python=2.7
activate my_project27
conda install matplotlib
Combine with pip
You can still use pip. conda "understands" what it is doing.
One snake is enough!
[This is for folks using the Linux Bash Shell on Windows 10.]
If you don't want to go the Anaconda route, you can install freetype (and png) by executing the following in the Windows 10 Bash shell:
sudo apt-get install freetype6-dev
The above command will also automatically install libpng. However, due to an error, the system will not 'realize' it has installed freetype, so you'll need to manually install pkg-config:
sudo apt-get install pkg-config
Thereafter you should be able to install matplotlib via pip without further incident.
sudo pip install matplotlib
I tired downloading matplotlib 2.2.2 with python 3.9.5, getting freetype & png errors for hours.
After downloading python 3.7.9 and removing python 3.9.5 from environment variables, installing matplotlib 2.2.2 worked with no problems!
Change your Python Version
Go to https://www.python.org/downloads/windows/, control-f search 3.7.9 and use the webinstaller. Follow all the recommended instructions
In pyvenv.cfg in your project directory switch version number to 3.7.9 and home to C:.....\Python37.
pip3 install alpaca-backtrader-api

too many pythons on linux

i recently started using python with xubuntu on virtualbox but i'm having problems. I want to be able to use numpy so i thought that apt-get install python-numpy would solve everything, but using the shell i kept getting No module named numpy. I used IDLE and it could find it. I also have IDLE (using Python-2.7), and again it could import numpy. Then i noticed that the shell had python 2.7.9, while the IDLEs had python 2.7.6.
Using
import sys
print sys.path
this if what i get from 2.7.9 (shell)
/usr/local/lib/python2.7/site-packages/setuptools-17.0-py2.7.egg
/usr/local/lib/python2.7/site-packages/Pillow-2.3.0-py2.7-linux-x86_64.egg
/usr/local/lib/python2.7/site-packages/mock-1.0.1-py2.7.egg
/usr/local/lib/python27.zip
/usr/local/lib/python2.7
/usr/local/lib/python2.7/plat-linux2
/usr/local/lib/python2.7/lib-tk
/usr/local/lib/python2.7/lib-old
/usr/local/lib/python2.7/lib-dynload
/usr/local/lib/python2.7/site-packages
and from 2.7.6 (IDLE)
/home/alessandro
/usr/bin
/usr/lib/python2.7
/usr/lib/python2.7/plat-x86_64-linux-gnu
/usr/lib/python2.7/lib-tk
/usr/lib/python2.7/lib-old
/usr/lib/python2.7/lib-dynload
/usr/local/lib/python2.7/dist-packages
/usr/lib/python2.7/dist-packages
/usr/lib/python2.7/dist-packages/PILcompat
/usr/lib/python2.7/dist-packages/gtk-2.0
/usr/lib/pymodules/python2.7
/usr/lib/python2.7/dist-packages/ubuntu-sso-client
I understand that i have two versions of python installed and somehow i ended up installing packageg into only one of them (the 2.7.6).
I'd like to be able to use 2.7.9 both in the shell and in IDLE and also i'd like to install so that python 2.7.9 can see them.
I read that i can add paths to the python sys.path, but isn't there a more efficient/persistent way to do what i want?
PS: tell me if you need more informations
For my projects I usually create a virtualenv for each python version I need for the project at hand. I manage them using pip to install specific versions that I need. Moreover you should be able to choose the python path in your IDE. While I'm not using IDLE, I read here that apparently idle comes along with the python versions during install. So maybe your idle versions collide with each other. If you want to have only one python version at the time on your machine you might consider a simple remove and fresh install of your desired version. Again I would recommend pip over apt-get etc. Hope this is of help for you.
Worth to check PyDev, a plugin for Eclipse to work on python.
http://marketplace.eclipse.org/content/pydev-python-ide-eclipse , or http://pydev.org/.
This allows you to configure the python version for different project's.
I have some project's with python 2.7 and others with 3.4.
it's checks the whole system in search for the PYTHONPATH to use!

where packages are stored in python (trying to install dragnet)

I've been struggling to install a python package called dragnet and its dawned on me just how little I understand about where packages are stored and how they are accessed in python. When I do import X in python, what steps does python take to try to import the packages?
I have anaconda installed, and it looks like many are stored in ~/anaconda/pkgs with names like "argcomplete-0.8.4-py27_0".
A bunch of other packages are in /Library/Python/2.7/site-packages. Sometimes conda install X doesnt work, but pip install will (conda pip is depreciated), and in these cases packages will often end up here. Both planout and dragnet are examples of such packages.
Dragnet, however, didn't want to import even despite its presence in /Library/Python/2.7/site-packages. When I go directly into the folder /Library/Python/2.7/site-packages in ipython it will import ok. I could not figure out where to put it or how to make it accessible when not in the folder though? I'd appreciate a pointer to a good tutorial or overview about packaging, package locations and importing in python.
In cases in which you are unable to install with anaconda, and you need to install another way, and that other way ends up with the install being not in the anaconda packages folder (lets say you end up with a new install in /Library/Python/2.7/site-packages), a reasonable work around is the following:
import sys
sys.path.append('/Library/Python/2.7/site-packages')
import desired_package_found_in_that_folder
This will force python to look in that folder for packages.
Instead of installing packages globally use Virtualenv to create virtual environments. This will help you isolate different projects and will also make dependency and package management much easier.
Read the docs here: https://virtualenv.pypa.io/en/latest/