AttributeError: 'NoneType' object has no attribute 'startswith'

anaconda pip 错误，返回 AttributeError: 'NoneType' object has no attribute 'startswith'

解决办法：

参见 https://stackoverflow.com/questions/46260169/python-locationvalueerror-no-host-specified
修改windows注册表 

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings \ ProxyEnable

删除 ProxyEnable 

新建DWORD(32位)值

 (REG_DWORD
0x00000000(0))

 Traceback (most recent call last):

      File "C:\Anaconda\lib\site-packages\conda\exceptions.py", line 634, in conda_exception_handler

        return_value = func(*args, **kwargs)

      File "C:\Anaconda\lib\site-packages\conda\cli\main.py", line 140, in _main

        exit_code = args.func(args, p)

      File "C:\Anaconda\lib\site-packages\conda\cli\main_update.py", line 65, in execute

        install(args, parser, 'update')

      File "C:\Anaconda\lib\site-packages\conda\cli\install.py", line 228, in install

        unknown=index_args['unknown'], prefix=prefix)

      File "C:\Anaconda\lib\site-packages\conda\core\index.py", line 101, in get_index

        index = fetch_index(channel_priority_map, use_cache=use_cache)

      File "C:\Anaconda\lib\site-packages\conda\core\index.py", line 120, in fetch_index

        repodatas = collect_all_repodata(use_cache, tasks)

      File "C:\Anaconda\lib\site-packages\conda\core\repodata.py", line 74, in collect_all_repodata

        repodatas = _collect_repodatas_serial(use_cache, tasks)

      File "C:\Anaconda\lib\site-packages\conda\core\repodata.py", line 479, in _collect_repodatas_serial

        for url, schan, pri in tasks]

      File "C:\Anaconda\lib\site-packages\conda\core\repodata.py", line 479, in <listcomp>

        for url, schan, pri in tasks]

      File "C:\Anaconda\lib\site-packages\conda\core\repodata.py", line 109, in func

        res = f(*args, **kwargs)

      File "C:\Anaconda\lib\site-packages\conda\core\repodata.py", line 458, in fetch_repodata

        mod_etag_headers.get('_mod'))

      File "C:\Anaconda\lib\site-packages\conda\core\repodata.py", line 138, in fetch_repodata_remote_request

        timeout=timeout)

      File "C:\Anaconda\lib\site-packages\requests\sessions.py", line 531, in get

        return self.request('GET', url, **kwargs)

      File "C:\Anaconda\lib\site-packages\requests\sessions.py", line 518, in request

        resp = self.send(prep, **send_kwargs)

      File "C:\Anaconda\lib\site-packages\requests\sessions.py", line 639, in send

        r = adapter.send(request, **kwargs)

      File "C:\Anaconda\lib\site-packages\requests\adapters.py", line 438, in send

        timeout=timeout

      File "C:\Anaconda\lib\site-packages\requests\packages\urllib3\connectionpool.py", line 594, in urlopen

        self._prepare_proxy(conn)

      File "C:\Anaconda\lib\site-packages\requests\packages\urllib3\connectionpool.py", line 810, in _prepare_proxy

        conn.connect()

      File "C:\Anaconda\lib\site-packages\requests\packages\urllib3\connection.py", line 284, in connect

        conn = self._new_conn()

      File "C:\Anaconda\lib\site-packages\requests\packages\urllib3\connection.py", line 141, in _new_conn

        (self.host, self.port), self.timeout, **extra_kw)

      File "C:\Anaconda\lib\site-packages\requests\packages\urllib3\util\connection.py", line 51, in create_connection

        if host.startswith('['):

    AttributeError: 'NoneType' object has no attribute 'startswith'