Question

我在运行此命令时安装NLTK时出现以下错误

sudo pip install -U nltk

例外：

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/pip-6.0.8-py2.7.egg/pip/basecommand.py", line 232, in main
    status = self.run(options, args)
  File "/usr/local/lib/python2.7/dist-packages/pip-6.0.8-py2.7.egg/pip/commands/install.py", line 305, in run
    name, None, isolated=options.isolated_mode,
  File "/usr/local/lib/python2.7/dist-packages/pip-6.0.8-py2.7.egg/pip/req/req_install.py", line 181, in from_line
    isolated=isolated)
  File "/usr/local/lib/python2.7/dist-packages/pip-6.0.8-py2.7.egg/pip/req/req_install.py", line 54, in init
    req = pkg_resources.Requirement.parse(req)
  File "/usr/local/lib/python2.7/dist-packages/pip-6.0.8-py2.7.egg/pip/_vendor/pkg_resources/init.py", line 2873, in parse
    reqs = list(parse_requirements(s)) 
  File "/usr/local/lib/python2.7/dist-packages/pip-6.0.8-py2.7.egg/pip/_vendor/pkg_resources/init.py", line 2807, in parse_requirements
    raise ValueError("Missing distribution spec", line)
ValueError: ('Missing distribution spec', '\xe2\x80\x90U')

Answer 1

最有可能的是，您已经从某个网页（或PDF）剪切并粘贴了这一行。该网页可能将ASCII hyphen (minus sign)更改为U+2010 HYPHEN。

因此，您需要输入命令

sudo pip install -U nltk   # This uses the usual ASCII hyphen

不剪切和粘贴：

sudo pip install ‐U nltk   # This uses U+2010 HYPHEN

错误消息

raise ValueError("Missing distribution spec", line)
ValueError: ('Missing distribution spec', '\xe2\x80\x90U')

表示line是字符串'\xe2\x80\x90U'。

这个utf-8编码的字符串看起来像连字符和U：

In [90]: print('\xe2\x80\x90U')
‐U

但请注意，泛滥不是通常的ASCII泛滥（chr(45)）。相反，它是utf-8编码的U + 2010 HYPHEN：

In [93]: import unicodedata as UD

In [95]: UD.name('\xe2\x80\x90'.decode('utf-8'))
Out[95]: 'HYPHEN'

In [102]: hex(ord('\xe2\x80\x90'.decode('utf-8')))
Out[102]: '0x2010'

而不是通常的连字符chr(45)，即（utf-8编码）U+002D HYPHEN-MINUS：

In [97]: UD.name('-'.decode('utf-8'))
Out[97]: 'HYPHEN-MINUS'

In [4]: hex(ord('-'.decode('utf-8')))
Out[4]: '0x2d'

In [98]: ord('-')
Out[98]: 45

在Ubuntu 14.4和Python 2.7中安装NLTK时出现异常错误

1 个答案: