Multiple Python installations on OS X

gistfile1.md

Previous versions used homebrew to install the various versions. As suggested in the comments, it's better to use pyenv instead. If you are looking for the previous version of this document, see the revision history.

$ brew update
$ brew install pyenv
$ pyenv install 3.5.0
$ pyenv install 3.4.3
$ pyenv install 3.3.6
$ pyenv install 3.2.6
$ pyenv install 2.7.10
$ pyenv install 2.6.9
$ pyenv versions
* system (set by /Users/bouke/.pyenv/version)
  2.6.9
  2.7.10
  3.2.6
  3.3.6
  3.4.3
  3.5.0

Then, when you need a certain version:

pyenv local 3.5.0

This will create a file .python-version, so pyenv will remember the Python version for this directory. This works also nice with tox, as you can activate many Python version at once. See the pyenv documentation for more information.

See also Using tox and pyenv for testing and development for a more detailed how-to.

The Python 3.2 install will fail on newer versions of Homebrew because the formula is incompatible. I had to comment out lines 133-141 of Library/Formula/python3.rb and install Setuptools and Pip manually after the Python install finished.

Other than that, worked perfectly, thanks for taking the time to document this. :)

Thanks for this writeup -- very helpful. Also thanks tmhlinger for your tip.

The brew versions command has been removed. The instructions are no longer valid.

This worked perfectly for me, I just skipped the brew versions line.

I'm a Homebrew maintainer; I strongly suggest you use pyenv instead if you ever need anything but the most current Python versions. It's a much nicer solution in part because it's designed to handle switching scripts back and forth, which is very difficult for Homebrew to do.

Thanks, I didn't know about pyenv, but found very useful already. I've updated the document as this looks like a better way to do this.

The link is broken:

Using tox and pyenv for testing and development
http://tbb.co/using-tox-and-pyenv-for-testing-and-development/

I believe the new link is now here:

http://www.holger-peters.de/using-pyenv-and-tox.html

Thanks @denfromufa, I've updated the link.

Good to know, to not use default Python of OSX Sierra:

Add to your shell (~/.bashrc or ~/.zshrc) :

export PATH="/Users/username/.pyenv:$PATH"
eval "$(pyenv init -)"

Remplace username by your MacBook user.
Refresh your terminal env, example: $ source ~/.zshrc (or restart your terminal)

@matinfo it saves me :-)

@matinfo

Can also works using shims (pyenv doc):

export PATH="/shims:$PATH"
eval "$(pyenv init -)"

great thankyou!

Nice work~

Thanks!!

Thank you guys!

Thank you 👍

yes, very helpful!

pyenv install 3.7.2
python-build: use openssl from homebrew
python-build: use readline from homebrew
Downloading Python-3.7.2.tar.xz...
-> https://www.python.org/ftp/python/3.7.2/Python-3.7.2.tar.xz
Installing Python-3.7.2...
python-build: use readline from homebrew

BUILD FAILED (OS X 10.14.3 using python-build 20180424)

Inspect or clean up the working tree at /var/folders/g_/9zn58k_16m50w1z3tqvq65xr0000gn/T/python-build.20190214115852.93619
Results logged to /var/folders/g_/9zn58k_16m50w1z3tqvq65xr0000gn/T/python-build.20190214115852.93619.log

Last 10 log lines:
File "/private/var/folders/g_/9zn58k_16m50w1z3tqvq65xr0000gn/T/python-build.20190214115852.93619/Python-3.7.2/Lib/ensurepip/main.py", line 5, in
sys.exit(ensurepip.main())
File "/private/var/folders/g/9zn58k_16m50w1z3tqvq65xr0000gn/T/python-build.20190214115852.93619/Python-3.7.2/Lib/ensurepip/init.py", line 204, in main
default_pip=args.default_pip,
File "/private/var/folders/g/9zn58k_16m50w1z3tqvq65xr0000gn/T/python-build.20190214115852.93619/Python-3.7.2/Lib/ensurepip/init.py", line 117, in _bootstrap
return _run_pip(args + [p[0] for p in PROJECTS], additional_paths)
File "/private/var/folders/g/9zn58k_16m50w1z3tqvq65xr0000gn/T/python-build.20190214115852.93619/Python-3.7.2/Lib/ensurepip/init.py", line 27, in _run_pip
import pip._internal
zipimport.ZipImportError: can't decompress data; zlib not available
make: *** [install] Error 1

@crapthings

Try the following:

CFLAGS="-I$(brew --prefix readline)/include -I$(brew --prefix openssl)/include -I$(xcrun --show-sdk-path)/usr/include" LDFLAGS="-L$(brew --prefix readline)/lib -L$(brew --prefix openssl)/lib" PYTHON_CONFIGURE_OPTS=--enable-unicode=ucs2 pyenv install -v 3.7.2

reference:
pyenv/pyenv#1219

Yikes! I had the same error as @crapthings and the arcane incantation from @LongBu made my screen puke all fun kinds of output and eventually ended with:

Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Successfully installed pip-18.1 setuptools-40.6.2
/var/folders/rz/fjd3x9jn24n8kxhybt17yh_40000gn/T/python-build.20190224164731.13157 ~
~
Installed Python-3.7.2 to /Volumes/DATA_MAC/brad/.pyenv/versions/3.7.2

... and pyenv versions lists 3.7.2
Thank you.