python之尝试为 Python 3 安装 scikit-learn 时出现 "Cannot fetch index base URL"错误消息

我尝试为 Python 3 安装 scikit-learn。我通过以下方式进行安装:

virtualenv model_env 
source  model_env/bin/activate 
pip3 install sklearn 

因此，我收到以下错误消息:

Downloading/unpacking sklearn 
  Cannot fetch index base URL https://pypi.python.org/simple/ 
  Could not find any downloads that satisfy the requirement sklearn 
Cleaning up... 
No distributions at all found for sklearn 

我在 pandas 包中遇到了同样的问题，我已经使用以下命令解决了它:

sudo apt-get install python3-pandas 

不幸的是，同样的方法不适用于 sklearn

sudo apt-get install python3-sklearn 

已添加

当我用 scikit-learn 替换 sklearn 时，我遇到了同样的问题:

Downloading/unpacking scikit-learn 
  Cannot fetch index base URL https://pypi.python.org/simple/ 
  Could not find any downloads that satisfy the requirement scikit-learn 
Cleaning up... 
No distributions at all found for scikit-learn 

添加 2

根据推荐，我尝试将 pip 与 -vvv 结合使用。请注意，我使用 pip3 而不是 pip。这是我得到的结果:

Downloading/unpacking scikit-learn 
  Getting page https://pypi.python.org/simple/scikit-learn/ 
  Could not fetch URL https://pypi.python.org/simple/scikit-learn/: connection error: HTTPSConnectionPool(host='pypi.python.org', port=443): Max retries exceeded with url: /simple/scikit-learn/ (Caused by <class 'OSError'>: [Errno 101] Network is unreachable) 
  Will skip URL https://pypi.python.org/simple/scikit-learn/ when looking for download links for scikit-learn 
  Getting page https://pypi.python.org/simple/ 
  Could not fetch URL https://pypi.python.org/simple/: connection error: HTTPSConnectionPool(host='pypi.python.org', port=443): Max retries exceeded with url: /simple/ (Caused by <class 'OSError'>: [Errno 101] Network is unreachable) 
  Will skip URL https://pypi.python.org/simple/ when looking for download links for scikit-learn 
  Cannot fetch index base URL https://pypi.python.org/simple/ 
  URLs to search for versions for scikit-learn: 
  * https://pypi.python.org/simple/scikit-learn/ 
  Getting page https://pypi.python.org/simple/scikit-learn/ 
  Could not fetch URL https://pypi.python.org/simple/scikit-learn/: connection error: HTTPSConnectionPool(host='pypi.python.org', port=443): Max retries exceeded with url: /simple/scikit-learn/ (Caused by <class 'OSError'>: [Errno 101] Network is unreachable) 
  Will skip URL https://pypi.python.org/simple/scikit-learn/ when looking for download links for scikit-learn 
  Could not find any downloads that satisfy the requirement scikit-learn 
Cleaning up... 
  Removing temporary dir /tmp/pip_build_root... 
No distributions at all found for scikit-learn 
Exception information: 
Traceback (most recent call last): 
  File "/usr/lib/python3/dist-packages/pip/basecommand.py", line 122, in main 
    status = self.run(options, args) 
  File "/usr/lib/python3/dist-packages/pip/commands/install.py", line 278, in run 
    requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle) 
  File "/usr/lib/python3/dist-packages/pip/req.py", line 1178, in prepare_files 
    url = finder.find_requirement(req_to_install, upgrade=self.upgrade) 
  File "/usr/lib/python3/dist-packages/pip/index.py", line 277, in find_requirement 
    raise DistributionNotFound('No distributions at all found for %s' % req) 
pip.exceptions.DistributionNotFound: No distributions at all found for scikit-learn 
 
Storing debug log for failure in /home/rngorb/.pip/pip.log 

请您参考如下方法:

尝试使用

pip3 install scikit-learn