Appendix D. Install Python 3
By the time Python 3 is preinstalled on every machine, toasters will be replaced by 3-D printers that crank out daily doughnuts with sprinkles. Windows doesn’t have Python at all, and OS X, Linux, and Unix tend to have old versions. Until they catch up, you’ll probably need to install Python 3 yourself.
The following sections describe how to carry out these tasks:
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Find out what version of Python you have on your computer, if any
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Install the standard distribution of Python 3, if you don’t have it
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Install the Anaconda distribution of scientific Python modules
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Install
pipandvirtualenv, if you can’t modify your system -
Install
condaas an alternative topip
Most of the examples in this book were written and tested with Python 3.3, the most recent stable version at the time of writing. Some used 3.4, which was released during the editing process. The What’s New in Python page presents what was added in each version. There are many sources of Python and many ways to install a new version. In this appendix, I’ll describe two of these ways:
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If you just want the standard interpreter and libraries, I recommend going to the official language site.
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If you would like Python together with the standard library, and the great scientific libraries described in Appendix C, use Anaconda.
Install Standard Python
Go to the Python download page with your web browser. It tries to guess your operating system and present the appropriate choices, but if it guesses wrong, you can use these:
You’ll see a page similar to that shown in Figure D-1.
Figure D-1. Sample download page
Click the Download link for the most recent version. In our case, that’s 3.4.1. This takes you to an information page like the one shown in Figure D-2.
Figure D-2. Detail page for download
You need to scroll down the page to see the actual download link (Figure D-3).
Figure D-3. Bottom of page offering download
Click the download link to get to the actual release-specific page (Figure D-4).
Figure D-4. Files to download
Now, click the correct version for your computer.
Mac OS X
Click the Mac OS X 64-bit/32-bit installer link to download a Mac .dmg file. Double-click it after the download completes. A window with four icons opens. Right-click Python.mpkg and then, in the dialog box that opens, click Open. Click the Continue button three times or so to step through the legalese, and then, when the appropriate dialog box opens, click Install. Python 3 will be installed as /usr/local/bin/python3, leaving any existing Python 2 on your computer unchanged.
Windows
For Windows, download one of these:
To determine whether you have a 32-bit or 64-bit version of Windows, do the following:
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Click the Start button.
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Right-click Computer.
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Click Properties and find the bit value.
Click the appropriate installer (.msi file).
After it’s downloaded, double-click it and follow the installer directions.
Install Anaconda
Anaconda is an all-in-one installer with an emphasis on science: it includes Python, the standard library, and many useful third-party libraries. Until recently, it included Python 2 as its standard interpreter, although there was a workaround to install Python 3.
The new upgrade, Anaconda 2.0, installs the latest
version of Python and its standard library (3.4 when this was written).
Other goodies include libraries that we’ve talked about in this book:
beautifulsoup4, flask, ipython,
matplotlib, nose, numpy, pandas, pillow, pip,
scipy, tables, zmq, and many others.
It includes a cross-platform installation program called conda
that improves on pip;
we’ll talk about that shortly.
To install Anaconda 2, go to the download page for the Python 3 versions. Click the appropriate link for your platform (version numbers might have changed since this was written, but you can figure it out):
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To download for the Mac, click Anaconda3-2.0.0-MacOSX-x86_64.pkg. Double-click the file when it’s done downloading, and then follow the usual steps for installing Mac software. It will install everything to the anaconda directory under your home directory.
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For Windows, click the 32-bit version or 64-bit version. Double-click the .exe file after it downloads.
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For Linux, click the 32-bit version or 64-bit version. When it has downloaded, execute it (it’s a big shell script).
Note
Ensure that the name of the file you download starts with Anaconda3. If it starts with just Anaconda, that’s the Python 2 version.
Anaconda installs everything to its own directory
(anaconda under your home directory).
This means that it won’t interfere with any versions of Python that might already
be on your computer.
It also means that you don’t need any special permission
(names like admin or root) to install it either.
To see what packages are included, visit the Anaconda docs page and then, in the box at the top of the page, click “Python version: 3.4.” It listed 141 packages when I last looked.
After installing Anaconda 2, you can see what Santa put on your computer by typing this command:
$ ./conda list
# packages in environment at /Users/williamlubanovic/anaconda: # anaconda 2.0.0 np18py34_0 argcomplete 0.6.7 py34_0 astropy 0.3.2 np18py34_0 backports.ssl-match-hostname 3.4.0.2 <pip> beautiful-soup 4.3.1 py34_0 beautifulsoup4 4.3.1 <pip> binstar 0.5.3 py34_0 bitarray 0.8.1 py34_0 blaze 0.5.0 np18py34_0 blz 0.6.2 np18py34_0 bokeh 0.4.4 np18py34_1 cdecimal 2.3 py34_0 colorama 0.2.7 py34_0 conda 3.5.2 py34_0 conda-build 1.3.3 py34_0 configobj 5.0.5 py34_0 curl 7.30.0 2 cython 0.20.1 py34_0 datashape 0.2.0 np18py34_1 dateutil 2.1 py34_2 docutils 0.11 py34_0 dynd-python 0.6.2 np18py34_0 flask 0.10.1 py34_1 freetype 2.4.10 1 future 0.12.1 py34_0 greenlet 0.4.2 py34_0 h5py 2.3.0 np18py34_0 hdf5 1.8.9 2 ipython 2.1.0 py34_0 ipython-notebook 2.1.0 py34_0 ipython-qtconsole 2.1.0 py34_0 itsdangerous 0.24 py34_0 jdcal 1.0 py34_0 jinja2 2.7.2 py34_0 jpeg 8d 1 libdynd 0.6.2 0 libpng 1.5.13 1 libsodium 0.4.5 0 libtiff 4.0.2 0 libxml2 2.9.0 1 libxslt 1.1.28 2 llvm 3.3 0 llvmpy 0.12.4 py34_0 lxml 3.3.5 py34_0 markupsafe 0.18 py34_0 matplotlib 1.3.1 np18py34_1 mock 1.0.1 py34_0 multipledispatch 0.4.3 py34_0 networkx 1.8.1 py34_0 nose 1.3.3 py34_0 numba 0.13.1 np18py34_0 numexpr 2.3.1 np18py34_0 numpy 1.8.1 py34_0 openpyxl 2.0.2 py34_0 openssl 1.0.1g 0 pandas 0.13.1 np18py34_0 patsy 0.2.1 np18py34_0 pillow 2.4.0 py34_0 pip 1.5.6 py34_0 ply 3.4 py34_0 psutil 2.1.1 py34_0 py 1.4.20 py34_0 pycosat 0.6.1 py34_0 pycparser 2.10 py34_0 pycrypto 2.6.1 py34_0 pyflakes 0.8.1 py34_0 pygments 1.6 py34_0 pyparsing 2.0.1 py34_0 pyqt 4.10.4 py34_0 pytables 3.1.1 np18py34_0 pytest 2.5.2 py34_0 python 3.4.1 0 python-dateutil 2.1 <pip> python.app 1.2 py34_2 pytz 2014.3 py34_0 pyyaml 3.11 py34_0 pyzmq 14.3.0 py34_0 qt 4.8.5 3 readline 6.2 2 redis 2.6.9 0 redis-py 2.9.1 py34_0 requests 2.3.0 py34_0 rope 0.9.4 py34_1 rope-py3k 0.9.4 <pip> runipy 0.1.0 py34_0 scikit-image 0.9.3 np18py34_0 scipy 0.14.0 np18py34_0 setuptools 3.6 py34_0 sip 4.15.5 py34_0 six 1.6.1 py34_0 sphinx 1.2.2 py34_0 spyder 2.3.0rc1 py34_0 spyder-app 2.3.0rc1 py34_0 sqlalchemy 0.9.4 py34_0 sqlite 3.8.4.1 0 ssl_match_hostname 3.4.0.2 py34_0 sympy 0.7.5 py34_0 tables 3.1.1 <pip> tk 8.5.15 0 tornado 3.2.1 py34_0 ujson 1.33 py34_0 werkzeug 0.9.4 py34_0 xlrd 0.9.3 py34_0 xlsxwriter 0.5.5 py34_0 yaml 0.1.4 1 zeromq 4.0.4 0 zlib 1.2.7 1
Install and Use pip and virtualenv
The pip package is the most popular way to install
third-party (nonstandard) Python packages.
It has been annoying that such a useful tool isn’t part of standard Python,
and that you’ve needed to download and install it yourself.
As a friend of mine used to say,
it’s a cruel hazing ritual.
The good news is that pip is a standard part of Python,
starting with the 3.4 release.
Often used with pip,
the virtualenv program is a way to install Python packages in
a specified directory (folder)
to avoid interactions with any preexisting system Python packages.
This lets you use whatever Python goodies you want,
even if you don’t have permission to change the existing installation.
If you have Python 3
but only the Python 2 version of pip,
here’s how to get the Python 3 version on Linux or OS X:
$ curl -O http://python-distribute.org/distribute_setup.py $ sudo python3 distribute_setup.py $ curl -O https://raw.github.com/pypa/pip/master/contrib/get-pip.py $ sudo python3 get-pip.py
This installs pip-3.3 in the bin directory
of your Python 3 installation.
Then, use pip-3.3 to install third-party Python packages
rather than Python 2’s pip.
Some good guides to pip and virtualenv are:
Install and Use conda
Until recently, pip always downloaded source files rather than binaries.
This can be a problem with Python modules that are built on C libraries.
Recently, the Anaconda developers built
conda to address the problems
they’ve seen with pip and other tools.
pip is a Python package manager, but conda works with any software and language.
conda also avoids the need for something like virtualenv to keep installations
from stepping on one another.
If you installed the Anaconda distribution, you already have the conda program.
If not, you can get Python 3 and conda from the
miniconda page.
As with Anaconda, make sure the file you download starts with Miniconda3;
if it starts with Miniconda alone, it’s the Python 2 version.
conda works with pip.
Although it has its own public package repository,
commands like conda search will also search the PyPi repository.
If you have problems with pip, conda might be a good alternative.