Python中Pip的安装操作

Python有两个著名的包管理工具easy_install和pip。在Python2.7的安装包中，easy_install是默认安装的，而pip需要我们手动安装。随着Python版本的提高，easy_install已经逐渐被淘汰，但是一些比较老的第三方库，在现在仍然只能通过easy_install进行安装。目前，pip已经成为主流的安装工具，自Python2 >=2.7.9或者Python3.4以后默认都安装有pip。

如果很不巧，你的Python版本下恰好没有pip这个工具，怎么办呢？解决办法很多！

1. 使用easy_install安装： 各种进入到easy_install脚本的目录下，然后运行easy_inatall pip
2. 使用get-pip.py安装： 在下面的url下载get-pip.py脚本 curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py 然后运行：python get-pip.py 这个脚本会同时安装setuptools和wheel工具。
3. 在linux下使用包管理工具安装pip： 例如，ubuntu下：sudo apt-get install python-pip。Fedora系下：sudo yum install python-pip
4. 在windows下安装pip： 在C:\python27\scirpts下运行easy_install pip进行安装。

刚安装完毕的pip可能需要先升级一下自身： 在Linux或masOS中：pip install -U pip 在windows中：python -m pip install -U pip

get-pip.py安装

以方法2. 使用get-pip.py安装，为例

1、新建一个文本文档，起名为get-pip，后缀名该为.py

2、打开网址https://bootstrap.pypa.io/get-pip.py，复制所有文字到我们新建的文件get-pip.py中

源代码中 DATA = b"“” 乱码 “”"，，，DATA 后面注释的乱码有3万多行，我直接给删了，不影响

下面是我实际可运行的代码

#!/usr/bin/env python
#
# Hi There!
#
# You may be wondering what this giant blob of binary data here is, you might
# even be worried that we're up to something nefarious (good for you for being
# paranoid!). This is a base85 encoding of a zip file, this zip file contains
# an entire copy of pip (version 22.3.1).
#
# Pip is a thing that installs packages, pip itself is a package that someone
# might want to install, especially if they're looking to run this get-pip.py
# script. Pip has a lot of code to deal with the security of installing
# packages, various edge cases on various platforms, and other such sort of
# "tribal knowledge" that has been encoded in its code base. Because of this
# we basically include an entire copy of pip inside this blob. We do this
# because the alternatives are attempt to implement a "minipip" that probably
# doesn't do things correctly and has weird edge cases, or compress pip itself
# down into a single file.
#
# If you're wondering how this is created, it is generated using
# `scripts/generate.py` in https://github.com/pypa/get-pip.

import sys

this_python = sys.version_info[:2]
min_version = (3, 7)
if this_python < min_version:
    message_parts = [
        "This script does not work on Python {}.{}".format(*this_python),
        "The minimum supported Python version is {}.{}.".format(*min_version),
        "Please use https://bootstrap.pypa.io/pip/{}.{}/get-pip.py instead.".format(*this_python),
    ]
    print("ERROR: " + " ".join(message_parts))
    sys.exit(1)


import os.path
import pkgutil
import shutil
import tempfile
import argparse
import importlib
from base64 import b85decode


def include_setuptools(args):
    """
    Install setuptools only if absent and not excluded.
    """
    cli = not args.no_setuptools
    env = not os.environ.get("PIP_NO_SETUPTOOLS")
    absent = not importlib.util.find_spec("setuptools")
    return cli and env and absent


def include_wheel(args):
    """
    Install wheel only if absent and not excluded.
    """
    cli = not args.no_wheel
    env = not os.environ.get("PIP_NO_WHEEL")
    absent = not importlib.util.find_spec("wheel")
    return cli and env and absent


def determine_pip_install_arguments():
    pre_parser = argparse.ArgumentParser()
    pre_parser.add_argument("--no-setuptools", action="store_true")
    pre_parser.add_argument("--no-wheel", action="store_true")
    pre, args = pre_parser.parse_known_args()

    args.append("pip")

    if include_setuptools(pre):
        args.append("setuptools")

    if include_wheel(pre):
        args.append("wheel")

    return ["install", "--upgrade", "--force-reinstall"] + args


def monkeypatch_for_cert(tmpdir):
    """Patches `pip install` to provide default certificate with the lowest priority.

    This ensures that the bundled certificates are used unless the user specifies a
    custom cert via any of pip's option passing mechanisms (config, env-var, CLI).

    A monkeypatch is the easiest way to achieve this, without messing too much with
    the rest of pip's internals.
    """
    from pip._internal.commands.install import InstallCommand

    # We want to be using the internal certificates.
    cert_path = os.path.join(tmpdir, "cacert.pem")
    with open(cert_path, "wb") as cert:
        cert.write(pkgutil.get_data("pip._vendor.certifi", "cacert.pem"))

    install_parse_args = InstallCommand.parse_args

    def cert_parse_args(self, args):
        if not self.parser.get_default_values().cert:
            # There are no user provided cert -- force use of bundled cert
            self.parser.defaults["cert"] = cert_path  # calculated above
        return install_parse_args(self, args)

    InstallCommand.parse_args = cert_parse_args


def bootstrap(tmpdir):
    monkeypatch_for_cert(tmpdir)

    # Execute the included pip and use it to install the latest pip and
    # setuptools from PyPI
    from pip._internal.cli.main import main as pip_entry_point
    args = determine_pip_install_arguments()
    sys.exit(pip_entry_point(args))


def main():
    tmpdir = None
    try:
        # Create a temporary working directory
        tmpdir = tempfile.mkdtemp()

        # Unpack the zipfile into the temporary directory
        pip_zip = os.path.join(tmpdir, "pip.zip")
        with open(pip_zip, "wb") as fp:
            fp.write(b85decode(DATA.replace(b"\n", b"")))

        # Add the zipfile to sys.path so that we can import it
        sys.path.insert(0, pip_zip)

        # Run the bootstrap
        bootstrap(tmpdir=tmpdir)
    finally:
        # Clean up our temporary working directory
        if tmpdir:
            shutil.rmtree(tmpdir, ignore_errors=True)
 

DATA = b"""
""" 

if __name__ == "__main__":
    main()

代码开头的一段说明文字

你可能想知道这一大块二进制数据是什么
甚至担心我们在做一些邪恶的事情(对你来说是件好事
偏执!)这是一个base85编码的zip文件，这个zip文件包含pip的完整副本(版本22.3.1)。

pip是一个安装包的东西，pip本身就是一个包
可能想要安装，特别是如果他们想要运行这个get-pip.py脚本。
Pip有很多代码来处理安装的安全性包，各种平台上的各种边缘情况，等等
“部落知识”已被编码在其代码库中。正因为如此我们基本上在这个blob中包含了PIP的完整副本。
我们这样做因为替代方案是试图实现一个“小程序”，可能
不能正确地做事情，并且有奇怪的边缘情况，或者压缩pip本身分解成一个文件。

如果你想知道这是如何创建的，它是使用
https://github.com/pypa/get-pip中的' scripts/generate.py '

3、打开cmd，找到get-pip.py文件的路径 ，然后输入python get-pip.py，敲回车就开始安装

4、安装完成后，可以在cmd中输入pip list测试一下，显示如下信息就是安装成功了。

5、如果没有显示，则需要回到python的安装目录，将scripts目录加到path环境变量中，然后重启cmd