Python 初步使用pip安装第三方库

Python提供了很多内置库，当我们要编程玩出新花样的话就可以用一些外置库了，Python有很多种下载外置库的方法，可以去库的官网下载，也可以通过命令指示符下载，今天教大家如何用Windows命令指示符下载Python库。

使用Windows徽标+R快捷键弹出如图窗口

 在输入框中输入cmd按回车进入命令指示符。

在命令指示符中输入pip就会弹出以下帮助内容

Usage:
  pip  [options]

Commands:
  install                     Install packages.
  download                    Download packages.
  uninstall                   Uninstall packages.
  freeze                      Output installed packages in requirements format.
  list                        List installed packages.
  show                        Show information about installed packages.
  check                       Verify installed packages have compatible dependencies.
  config                      Manage local and global configuration.
  search                      Search PyPI for packages.
  cache                       Inspect and manage pip's wheel cache.
  wheel                       Build wheels from your requirements.
  hash                        Compute hashes of package archives.
  completion                  A helper command used for command completion.
  debug                       Show information useful for debugging.
  help                        Show help for commands.

General Options:
  -h, --help                  Show help.
  --isolated                  Run pip in an isolated mode, ignoring environment variables and user configuration.
  -v, --verbose               Give more output. Option is additive, and can be used up to 3 times.
  -V, --version               Show version and exit.
  -q, --quiet                 Give less output. Option is additive, and can be used up to 3 times (corresponding to
                              WARNING, ERROR, and CRITICAL logging levels).
  --log                 Path to a verbose appending log.
  --proxy              Specify a proxy in the form [user:passwd@]proxy.server:port.
  --retries          Maximum number of retries each connection should attempt (default 5 times).
  --timeout              Set the socket timeout (default 15 seconds).
  --exists-action     Default action when a path already exists: (s)witch, (i)gnore, (w)ipe, (b)ackup,
                              (a)bort.
  --trusted-host    Mark this host or host:port pair as trusted, even though it does not have valid or any
                              HTTPS.
  --cert                Path to alternate CA bundle.
  --client-cert         Path to SSL client certificate, a single file containing the private key and the
                              certificate in PEM format.
  --cache-dir            Store the cache data in .
  --no-cache-dir              Disable the cache.
  --disable-pip-version-check
                              Don't periodically check PyPI to determine whether a new version of pip is available for
                              download. Implied with --no-index.
  --no-color                  Suppress colored output
  --no-python-version-warning
                              Silence deprecation warnings for upcoming unsupported Pythons.

pip常用的方法有install安装、uninstall卸载、download下载

如果python版本是2.x的版本就使用pip install 模块 进行安装，如果是python3.x的版本就用pip3 install 模块 进行安装（p.s.我用3.6版本用pip也是可以的）

比如安装pygame模块

pip install pygame
或
pip3 install pygame

但是pip会自动安装最新版本，如果要安装旧版的话就可以像下面这样输入

pip install 模块名==版本

如果执行终端脚本的时候模块已经安装，那么系统会显示：

Requirement already satisfied: pygame in c:\users\xxx\appdata\local\programs\python\python36\lib\site-packages (2.0.1)

可以用下面方法卸载pygame模块

pip uninstall pygame

随后系统会向用户列出要删除的文件，并询问用户是否删除

Proceed (y/n)? y
  Successfully uninstalled pygame-2.0.1

如上图，输入y即可成功删除

如果想要查看pip版本就可以输入

pip -V
或
pip --version

以上就是pip的初步使用教程，感谢大家的支持！