现象

新手朋友们，你想用sklearn包的时候，安装这个包如果用

pip install sklearn

会报错：

Collecting sklearn Downloading
https://pypi.tuna.tsinghua.edu.cn/packages/46/1c/395a83ee7b2d2ad7a05b453872053d41449564477c81dc356f720b16eac4/sklearn-0.0.post12.tar.gz
(2.6 kB) Preparing metadata (setup.py) … error error:
subprocess-exited-with-error
× python setup.py egg_info did not run successfully. │ exit code: 1 ╰─> [15 lines of output]
The ‘sklearn’ PyPI package is deprecated, use ‘scikit-learn’
rather than ‘sklearn’ for pip commands.

  Here is how to fix this error in the main use cases:
  - use 'pip install scikit-learn' rather than 'pip install sklearn'
  - replace 'sklearn' by 'scikit-learn' in your pip requirements files
    (requirements.txt, setup.py, setup.cfg, Pipfile, etc ...)
  - if the 'sklearn' package is used by one of your dependencies,
    it would be great if you take some time to track which package uses
    'sklearn' instead of 'scikit-learn' and report it to their issue tracker
  - as a last resort, set the environment variable
    SKLEARN_ALLOW_DEPRECATED_SKLEARN_PACKAGE_INSTALL=True to avoid this error
  
  More information is available at
  https://github.com/scikit-learn/sklearn-pypi-package
  [end of output]
 note: This error originates from a subprocess, and is likely not a problem with pip. error: metadata-generation-failed

× Encountered error while generating package metadata. ╰─> See above
for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.

原因

sklearn 这个名称在 PyPI 里早已 弃用，官方包叫 scikit-learn。
当你执行 pip install sklearn 时，安装脚本会直接抛错并提示改用 scikit-learn。

解决方法

用下面这个安装指令来进行：

pip install scikit-learn

安装完后，在代码里引用，依然可以用：

import sklearn