As a popular open source development project, Python has an active supporting community of contributors and users that also make their software available for other Python developers to use under open source license terms.
This allows Python users to share and collaborate effectively, benefiting from the solutions others have already created to common (and sometimes even rare!) problems, as well as potentially contributing their own solutions to the common pool.
This guide covers the installation part of the process. For a guide to creating and sharing your own Python projects, refer to the 分发指南 .
注意
For corporate and other institutional users, be aware that many organisations have their own policies around using and contributing to open source software. Please take such policies into account when making use of the distribution and installation tools provided with Python.
pip
is the preferred installer program. Starting with Python 2.7.9, it is included by default with the Python binary installers.
a virtual environment is a semi-isolated Python environment that allows packages to be installed for use by a particular application, rather than being installed system wide
virtualenv
is a third party tools for creating virtual environments, it is defaults to installing
pip
into all created virtual environments.
the PyPI (Python 包索引) is a public repository of open source licensed packages made available for use by other Python users
the PPA (Python 打包管理局) are the group of developers and documentation authors responsible for the maintenance and evolution of the standard packaging tools and the associated metadata and file format standards. They maintain a variety of tools, documentation and issue trackers on both GitHub and BitBucket .
distutils
is the original build and distribution system first added to the Python standard library in 1998. While direct use of
distutils
is being phased out, it still laid the foundation for the current packaging and distribution infrastructure, and it not only remains part of the standard library, but its name lives on in other ways (such as the name of the mailing list used to coordinate Python packaging standards development).
The standard packaging tools are all designed to be used from the command line.
The following command will install the latest version of a module and its dependencies from the Python Packaging Index:
python -m pip install SomePackage
注意
For POSIX users (including Mac OS X and Linux users), the examples in this guide assume the use of a
虚拟环境
. You may install
virtualenv
to provide such environments using either pip (
pip
安装
virtualenv
) or through your system package manager (commonly called
virtualenv
or
python-virtualenv
).
For Windows users, the examples in this guide assume that the option to adjust the system PATH environment variable was selected when installing Python.
It’s also possible to specify an exact or minimum version directly on the command line. When using comparator operators such as
>
,
<
or some other special character which get interpreted by shell, the package name and the version should be enclosed within double quotes:
python -m pip install SomePackage==1.0.4 # specific version
python -m pip install "SomePackage>=1.0.4" # minimum version
Normally, if a suitable module is already installed, attempting to install it again will have no effect. Upgrading existing modules must be requested explicitly:
python -m pip install --upgrade SomePackage
More information and resources regarding
pip
and its capabilities can be found in the
Python 打包用户指南
.
These are quick answers or links for some common tasks.
pip
in versions of Python prior to Python 2.7.9?
¶
Python only started bundling
pip
with Python 2.7.9. For earlier versions,
pip
needs to be “bootstrapped” as described in the Python Packaging User Guide.
Passing the
--user
option to
python
-m
pip
安装
will install a package just for the current user, rather than for all users of the system.
A number of scientific Python packages have complex binary dependencies, and aren’t currently easy to install using
pip
directly. At this point in time, it will often be easier for users to install these packages by
other means
rather than attempting to install them with
pip
.
On Linux, Mac OS X and other POSIX systems, use the versioned Python commands in combination with the
-m
switch to run the appropriate copy of
pip
:
python2 -m pip install SomePackage # default Python 2
python2.7 -m pip install SomePackage # specifically Python 2.7
python3 -m pip install SomePackage # default Python 3
python3.4 -m pip install SomePackage # specifically Python 3.4
(appropriately versioned
pip
commands may also be available)
On Windows, use the
py
Python launcher in combination with the
-m
switch:
py -2 -m pip install SomePackage # default Python 2
py -2.7 -m pip install SomePackage # specifically Python 2.7
py -3 -m pip install SomePackage # default Python 3
py -3.4 -m pip install SomePackage # specifically Python 3.4
On Linux systems, a Python installation will typically be included as part of the distribution. Installing into this Python installation requires root access to the system, and may interfere with the operation of the system package manager and other components of the system if a component is unexpectedly upgraded using
pip
.
On such systems, it is often better to use a virtual environment or a per-user installation when installing packages with
pip
.
It is possible that
pip
does not get installed by default. One potential fix is:
python -m ensurepip --default-pip
There are also additional resources for installing pip.
Python has typically relied heavily on source based distribution, with end users being expected to compile extension modules from source as part of the installation process.
With the introduction of support for the binary
wheel
format, and the ability to publish wheels for at least Windows and Mac OS X through the Python Packaging Index, this problem is expected to diminish over time, as users are more regularly able to install pre-built extensions rather than needing to build them themselves.
Some of the solutions for installing
scientific software
that is not yet available as pre-built
wheel
files may also help with obtaining other binary extensions without needing to build them locally.
另请参阅