pip supports installing from a package index using a requirement specifier . Generally speaking, a requirement specifier is composed of a project name followed by optional version specifiers .
PEP 508 contains a full specification of the format of a requirement.
New in version 6.0: Support for environment markers.
New in version 19.1: Support for the direct URL reference form.
A requirement specifier comes in two forms:
name-based, which is composed of:
a package name (eg:
requests
)
optionally, a set of “extras” that serve to install optional dependencies (eg:
security
)
optionally, constraints to apply on the version of the package
optionally, environment markers
URL-based, which is composed of:
a package name (eg:
requests
)
optionally, a set of “extras” that serve to install optional dependencies (eg:
security
)
a URL for the package
optionally, environment markers
A few example name-based requirement specifiers:
SomeProject SomeProject == 1.3 SomeProject >= 1.2, < 2.0 SomeProject[foo, bar] SomeProject ~= 1.4.2 SomeProject == 5.4 ; python_version < '3.8' SomeProject ; sys_platform == 'win32' requests [security] >= 2.8.1, == 2.8.* ; python_version < "2.7"
注意
Use quotes around specifiers in the shell when using
>
,
<
, or when using environment markers.
Do not use quotes in requirement files. There is only one exception: pip v7.0 and v7.0.1 (from May 2015) required quotes around specifiers containing environment markers in requirement files.
A few example URL-based requirement specifiers:
pip @ https://github.com/pypa/pip/archive/22.0.2.zip requests [security] @ https://github.com/psf/requests/archive/refs/heads/main.zip ; python_version >= "3.11"
