使用 pip install、pip list 等时出现不同的错误消息答案

【问题标题】：Different error messages when using pip install, pip list ect使用 pip install、pip list 等时出现不同的错误消息
【发布时间】：2019-06-24 13:08:00
【问题描述】：

当我尝试解决另一个问题时 pip uninstall scikit-learn 之后，我收到了红色文本，例如：

pip install --upgrade pip
    Error checking for conflicts.
    Traceback (most recent call last):
          File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
        pip\_vendor\pkg_resources\__init__.py", line 2584, in version
            return self._version
          File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
        pip\_vendor\pkg_resources\__init__.py", line 2691, in __getattr__
            raise AttributeError(attr)
        AttributeError: _version

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_internal\commands\install.py", line 503, in _warn_about_conflicts
        package_set, _dep_info = check_install_conflicts(to_install)
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_internal\operations\check.py", line 108, in check_install_conflicts
        package_set, _ = create_package_set_from_installed()
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_internal\operations\check.py", line 47, in create_package_set_from_installe
    d
        package_set[name] = PackageDetails(dist.version, dist.requires())
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_vendor\pkg_resources\__init__.py", line 2589, in version
        raise ValueError(tmpl % self.PKG_INFO, self)
    ValueError: ("Missing 'Version:' header and/or METADATA file", Unknown [unknown
    version] (c:\users\james\appdata\local\programs\python\python37\lib\site-package
    s))



C:\Users\James>pip list
    Exception:
    Traceback (most recent call last):
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_vendor\pkg_resources\__init__.py", line 2584, in version
        return self._version
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_vendor\pkg_resources\__init__.py", line 2691, in __getattr__
        raise AttributeError(attr)
    AttributeError: _version

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_internal\cli\base_command.py", line 176, in main
        status = self.run(options, args)
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_internal\commands\list.py", line 148, in run
        self.output_package_listing(packages, options)
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_internal\commands\list.py", line 205, in output_package_listing
        data, header = format_for_columns(packages, options)
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_internal\commands\list.py", line 271, in format_for_columns
        row = [proj.project_name, proj.version]
      File "c:\users\james\appdata\local\programs\python\python37\lib\site-packages\
    pip\_vendor\pkg_resources\__init__.py", line 2589, in version
        raise ValueError(tmpl % self.PKG_INFO, self)
    ValueError: ("Missing 'Version:' header and/or METADATA file", Unknown [unknown
    version] (c:\users\james\appdata\local\programs\python\python37\lib\site-package
    s))

关于如何解决此问题的任何建议（Windows）。我什至不知道该搜索什么错误。任何建议都会是一种祝福！

【问题讨论】：

标签： python scikit-learn pip

【解决方案1】：

this Issue on the pip GitHub repository 解决了类似的问题。

在你的情况下建议是进入

c:\users\james\appdata\local\programs\python\python37\lib\site-packages

并且，对于每个以“-”开头的文件夹，删除它并重新安装相应的包。

【讨论】：

通常会删除每个看起来很奇怪的文件夹（不仅是那些以'-'开头的文件夹），即。 0ecorator、%ecorator、~ecorator 来自 decorator 包。
你也知道为什么他们用“-”代替第一个字符吗？在此过程中的哪个位置发生这种情况？
我也对这个感兴趣，删除带有-的包解决了我过去遇到的许多错误。