Develop Reference

Python pip install exact version if two versions, one generic and one local, exist

We have set up a local python package server for your internal python packages and serve also some packages which are hard to compile on windows. As numpy is one of these packages, there exist now two versions of numpy on our server:
numpy-1.13.0-cp35-none-win32.whl
numpy-1.13.0+mkl-cp35-cp35m-win32.whl
How can I instruct pip to install a specific version of these two? Running pip install numpy will pick the package with "mkl", but for some projects I want numpy without "mkl".
Edit:
The only way which works is the full URL to the package, which seems a little bit verbose.

From what I can remember, it's just a matter of writing the package's entire name.
If you need a guide:
https://pip.pypa.io/en/stable/reference/pip_install/#examples

How do I install Numpy for Python 2.7 on Windows?

I am trying to install numpy for python 2.7, I've downloaded the zip, unzipped it and was expecting a Windows download file (.exe), but there isn't one.
Which of these files do I use to install it?
I tried running the setup.py file but don't seem to be getting anywhere.
Thanks!!!

There is .exe file in SourceForge. This is this link below:
http://sourceforge.net/projects/numpy/files/NumPy/1.9.1/numpy-1.9.1-win32-superpack-python2.7.exe/download

Python on Windows, including rather complex science/math/statistics package builds? It should just work? Seriously, use a third-party distribution! There are plenty and they only exist as of the hassle you were observing.
While the other two answers are "okay", it would recommend another approach. Especially for the common Windows user the following approach is easy to maintain and easy to reproduce.
Let me quote from the SciPy website:
For most users, especially on Windows and Mac, the easiest way to
install the packages of the SciPy stack is to download one of these
Python distributions, which includes all the key packages:
[a list of Python distributions]
As you can see, people having experience with this topic tend to recommend using a third-party Python distribution.
I have so far used ActivePython, but Anaconda also appears to be a well-maintained project.
Whichever you take: it comes as a nice Windows installer and will give you a seamless Python experience.

You can find a very well maintained list of Python Libraries (including numpy) for Windows at this Homepage: http://www.lfd.uci.edu/~gohlke/pythonlibs/

Wasted a lot of time trying to install on Windows from various binaries and installers, which all seemed to install a broken version, until I found that this worked: navigate to the python install directory and do python .\site-packages\pip install numpy

Why isn't pip updating my numpy and scipy?

My problem is that pip won't update my Python Packages, even though there are no errors.
It is similar to this one, but I am still now sure what to do. Basically, ALL my packages for python appear to be ridiculously outdated, even after updating everything via pip. Here are the details:
I am using pip, version 1.5.6.
I am using Python, version 2.7.5
I am on a Mac OSX, verion 10.9.5.
Using that, I have:
My numpy version is 1.6.2.
My scipy version is 0.11.0.
My matplotlib version is 1.1.1.
Even after I try:
sudo pip uninstall numpy
Followed by:
sudo pip install numpy
They both complete successfully, but when I go into python and check the version of numpy, it is still the old one. (As are all the other packages).
Not sure what is going on here?... How can this be fixed? P.S. I am new to this, so I might need explicit instructions. Thanks. Also, if anyone wants, I can provide a screenshot of pip as it is installing numpy.
EDIT:
Commands I ran as per the comments:
$which -a pip
/usr/local/bin/pip
$ head -1 $(which pip)
#!/usr/bin/python
$ which -a python
/usr/bin/python

In OS X 10.9, Apple's Python comes with a bunch of pre-installed extra packages, in a directory named /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python. Including numpy.
And the way they're installed (as if by using easy_install with an ancient pre-0.7 version of setuptools, but not into either of the normal easy_install destinations), pip doesn't know anything about them.
So, what happens is that sudo pip install numpy installs a separate copy of numpy into '/Library/Python/2.7/site-packages'—but in your sys.path, the Extras directory comes before the site-packages directory, so import numpy still finds Apple's copy. I'm not sure why that is, but it's probably not something you want to monkey with.
So, how do you fix this?
The two best solutions are:
Use virtualenv, and install your numpy and friends into a virtual environment, instead of system-wide. This has the downside that you have to learn how to use virtualenv—but that's definitely worth doing at some point, and if you have the time to learn it now, go for it.
Upgrade to Python 3.x, either from a python.org installer or via Homebrew. Python 3.4 or later comes with pip, and doesn't come with any pip-unfriendly pre-installed packages. And, unlike installing a separate 2.7, it doesn't interfere with Apple's Python at all; python3 and python, pip3 and pip, etc., will all be separate programs, and you don't have to learn anything about how PATH works or any of that. This has the downside that you have to learn Python 3.x, which has some major changes, so again, a bit of a learning curve, but again, definitely worth doing at some point.
Assuming neither of those is possible, I think the simplest option is to use easy_install instead of pip, for the packages you want to install newer versions of any of Apple's "extras". You can get a full list of those by looking at what's in /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python. When you upgrade numpy, you probably also want to upgrade scipy and matplotlib; I think everything else there is unrelated. (You can of course upgrade PyObjC or dateutil or anything else you care about there, but you don't have to.)
This isn't an ideal solution; there are a lot of reasons easy_install is inferior to pip (e.g., not having an uninstaller, so you're going to have to remember where that /Library/blah/blah path is (or find it again by printout out sys.path from inside Python). I wouldn't normally suggest easy_install for anything except readline and pip itself (and then only with Apple's Python). But in this case, I think it's simpler than the other alternatives.

Old question, but I found it when trying to solve this issue, will post my solution.
I found #abarnert's diagnosis to be correct and helpful, but I don't like any of the solutions: I really want to upgrade the default version of numpy. The challenge is that the directory these guys are in (which #abarnert mentioned) cannot be touched even by sudo, as they are in this "wheel" group. In fact, if you go there and do sudo rm -rf blah, it will give you a permission denied error.
To get around this, we have to take drastic action:
Reboot the computer in recovery mode
Find the terminal and type csrutil disable
Reboot normally, then upgrade numpy with pip2 install --user --upgrade numpy (and same for any other packages that have this problem)
Repeat steps a and b, this time changing "disable" to "enable"
Note: "csrutil disable" is serious business that can destabilize your machine, I would use it only when absolutely necessary and re-enable it ASAP. But AFAIK it's the only way to upgrade Python packages in a wheel directory.

Rename the numpy and scipy versions installed by Apple in /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/ so it starts using the newer versions installed by Pip.

What version of scipy and matplotlib should I install on Mac Mountain Lion?

I wish to install python numpy, scipy, and matplotlib packages. I used the following:
sudo port install py27-numpy py27-scipy py27-matplotlib py27-ipython +notebook py27-pandas py27-sympy py27-nose
I was able to install and run numpy, but not scipy or matplotlib. I get an error, "No module named scipy", even though installation appeared to proceed normally. I suspect that this has something to do with the version of scipy and bumpy. I am running OS X Version 10.8.4, python 2.7.2 and numpy 1.6.1. I suspect the problem is either the version or the directory which scipy is installed; scipy is in /Users/myname/src/scipy. I couldn't find out where numpy is located (how can this be done? Spotlight search does not indicate file directory, and grep hangs). How can I install scipy and other packages?

It's hard to be 100% sure without a little more information, but I'm 99% sure…
Your problem is that you're installing all this stuff for the MacPorts Python, but then trying to run Apple's Python, which doesn't have any of it installed. (Part of the reason I suspect this is that Apple's Python is version 2.7.2, while MacPorts has been on 2.7.5 for a long time now. The other part of the reason is that this is exactly the same kind of problem people have when they install two different Python X.Y versions without realizing that's what they're doing.)
If you want to use the MacPorts Python, run /opt/local/bin/python instead of just python.
If you know what you're doing, you can change your PATH, or create a symlink, etc., but I suspect you will just confuse yourself further.
I personally think you'd be a lot happier just sticking to Apple's Python. You need to install a Fortran compiler with MacPorts (or Homebrew, or manually, or …), but to install Python packages, just use pip.
(At this point, that last bit of advice probably won't help you, as the first pip on your PATH is probably the MacPorts one, and doesn't match the first python on your PATH. But if you're willing to start over, just port uninstall python, and then look at these blog posts or the dozens of related questions here on SO.)

What is the best way to install python 2 on OS X?

A colleague of mine wants to use my python 2 code on his OS X (10.6) machine. My code imports several built-in python packages, including Tkinter and shelve, and also uses third-party packages, including numpy, scipy, matplotlib, and ipython.
I've encountered a few problems with OS X's built-in python. (IDLE doesn't work, for example*). I suspect I should install a more recent version of python, and a different version of Tk.
My questions:
Will having two different versions of python/Tk on the same machine cause problems?
I would like to associate the terminal commands 'python', 'ipython', and 'easy_install' with the more recent version of python. How should I do this?
When I install third-party packages like numpy using a .dmg file, how do I control which version of python numpy installs into?
Is there a better way to do this?
If this process goes well, I'd consider adding OS X instructions to my code's documentation, so I'd like to boil down this process to the simplest, most general approach.
*EDIT: Also, this
EDIT: Thank you everyone for the useful answers. My colleague tried MacPorts, which seems to work well, but has a few speedbumps. First we had to install Xcode from the system install disk. This is not a fast or lightweight install (several GB). Luckily we still had the disk! Once Xcode was installed, MacPorts was easy to install. Python and the python subpackages we needed were also easy to install, but he told me this installation took several hours. Presumably this delay is due to compilation? He had an easy time setting the MacPorts python as default. However, I think we have to change the 'Python Launcher' application by hand, this seems to still default to the system python.
Even though he has a working system now, I'm tempted to ask him to try one of the other solutions. I'm not sure all of my code's potential users will tolerate a multi-hour, multi-gigabyte installation.

I use brew to install all my libraries/compilers/interpreters.
To install python try this:
brew install python
Then add Python's binaries directory to your $PATH in your ~/.profile:
export PATH=`brew --prefix python`/bin:$PATH
I'd recommend you to install pip, virtualenv and virtualenvwrapper to have better control over your environment too.

Have you tried ActivePython?
It includes a package manager (PyPM) that, by default, installs into your home directory (eg: ~/Library/Python/2.7). Main scripts get symlinked in /usr/local/bin; use the included pythonselect to set the active Python version.
You don't have to bother installing .dmg packages, as PyPM is a binary package manager ... therefore you can install non-pure Python packages like NumPy without having to compile things yourself.
ActivePython can use Apple's Tcl/Tk or, if installed, ActiveTcl.
A "simplest, most general approach" in your documentation could be:
Install ActivePython 2.7
Open Terminal and type pypm-2.7 install matplotlib ipython

Using MacPorts, you can install python 2.6, 2.7, 3.1 and 3.2 at the same time, with their own packages, without ever touching the built-in python.
numpy, scipy, matplotlib, and ipython are also available as ports for most of those python versions.
Moreover, if you install the python_select port, you'll be able:
to choose which one of those (plus the built-in python) is the "default" python;
to install python packages through easy_install/pip for the "selected" python, if they're not available as ports.
Add virtualenv to the mix, and you'll have a very, very flexible Python development environment.
As for your questions:
Q1: with MacPorts, no. while not a frequent user, I've installed and used matplotlib in 2.6 and 2.7, switching between the two using python_select.
Q2: easy_install, pip, ipython will be "linked" to the python they were installed by. (but see tip 1)
Q3: it's easier to install one of the py{26,27,xx}-numpy ports, or pip install numpy under your python_select'ed python.
Q4: well, MacPorts is the best thing I know after APT on Debian/Ubuntu... :-)
Now, two tips if you try MacPorts:
MacPorts cleanly installs ports separately from the OS X installation, in an /opt/local directory, and each python version is installed in a /opt/local/Library/Frameworks/Python.framework/Versions/{2.5,2.6,2.7,...} directory. Using python_select cleanly switch the "python" command using links. BUT... the Versions/{2.5,2.6,2.7,...}/bin directory, where python scripts are installed, is not added to the PATH. Just adding: export PATH=/opt/local/Library/Frameworks/Python.framework/Versions/Current/bin:$PATH to your ~/.profile will always give you direct access to the scripts installed for the selected python.
to avoid bad surprises, I've added a echo Selected python is \"$(python_select -s)\" line to my ~/.profile, so I always know which is my currently selected python when opening a session... :-)
Regards,
Georges

In almost all cases, the best python to use is the one from http://python.org/. It sets up the paths correctly and doesn't overwrite anything. DMG package installs usually work automatically, as does python setup.py install, and it's not too hard to get setuptools to work. If you want per-user installs, it is easy to set up .pydistutils.cfg and python automatically recognizes the path install_lib = ~/Library/Python/$py_version_short/site-packages

An addendum regarding the usage of brew:
Since some time, brew install python will install python3.
If you intend to install python2, you want to use
brew install python#2
It is perfectly fine to install both python and python3 using brew!

Here is an old post that answers your questions too.
In general it is not a problem at all to have more than one python installation on your machine. You just have to watch out which one you are calling on the command line.
>> which python
... helps to identify where your python binary is located. The original Mac OS X python is usually at "/usr/bin/python"
I personally use the MacPorts python installation. It also supports you with the installation of modules. (see link above)

I have 4 versions of python on my MacBook Pro. 2 from the original install of OS X 10.6 and a subsequent update, then self installed copies of python 2.7 and 3.2. You can update the python command to point at any of the versions. They all install in separate directories and cause no problems with each other.
I'm not sure what will happen when you install from a .dmg file. I believe it will simply use whatever version python points to.
This post on superuser.com answers your questions on changing default paths.