Many of the answers here are out of date for 2015 (although the accepted one is not). Here’s the current state of things:
- Binary packages are now distributed as wheels (
.whlfiles)—not just on PyPI, but in third-party repositories like Christoph Gohlke’s Extension Packages for Windows.
pipcan handle wheels;
- Virtual environments (which come built-in with 3.4, or can be added to 2.6+/3.1+ with
virtualenv) have become a very important and prominent tool (and recommended in the official docs); they include
pipout of the box, but don’t even work properly with
distributepackage that included
easy_installis no longer maintained. Its improvements over
setuptoolsgot merged back into
setuptools. Trying to install
distributewill just install
easy_installitself is only quasi-maintained.
- All of the cases where
pipused to be inferior to
easy_install—installing from an unpacked source tree, from a DVCS repo, etc.—are long-gone; you can
pip install .,
pip install git+https://.
pipcomes with the official Python 2.7 and 3.4+ packages from python.org, and a
pipbootstrap is included by default if you build from source.
- The various incomplete bits of documentation on installing, using, and building packages have been replaced by the Python Packaging User Guide. Python’s own documentation on Installing Python Modules now defers to this user guide, and explicitly calls out
pipas “the preferred installer program”.
- Other new features have been added to
pipover the years that will never be in
easy_install. For example,
pipmakes it easy to clone your site-packages by building a requirements file and then installing it with a single command on each side. Or to convert your requirements file to a local repo to use for in-house development. And so on.
The only good reason that I know of to use
easy_install in 2015 is the special case of using Apple’s pre-installed Python versions with OS X 10.5-10.8. Since 10.5, Apple has included
easy_install, but as of 10.10 they still don’t include
pip. With 10.9+, you should still just use
get-pip.py, but for 10.5-10.8, this has some problems, so it’s easier to
sudo easy_install pip. (In general,
easy_install pip is a bad idea; it’s only for OS X 10.5-10.8 that you want to do this.) Also, 10.5-10.8 include
readline in a way that
easy_install knows how to kludge around but
pip doesn’t, so you also want to
sudo easy_install readline if you want to upgrade that.