Python 使用波特词干分析器时的NLTK输入错误

我正在导入nltk，但它给出了以下错误

Traceback (most recent call last):
  File "/home/control/Work/Intelligence/Datasets/whats cooking/new.py", line 4, in <module>
    import nltk
  File "/usr/local/lib/python2.7/dist-packages/nltk-3.0.5-py2.7.egg/nltk/__init__.py", line 137, in <module>
    from nltk.stem import *
  File "/usr/local/lib/python2.7/dist-packages/nltk-3.0.5-py2.7.egg/nltk/stem/__init__.py", line 29, in <module>
    from nltk.stem.snowball import SnowballStemmer
  File "/usr/local/lib/python2.7/dist-packages/nltk-3.0.5-py2.7.egg/nltk/stem/snowball.py", line 25, in <module>
    from nltk.stem import porter
ImportError: cannot import name porter

回溯（最近一次呼叫最后一次）：
文件“/home/control/Work/Intelligence/Datasets/whats cooking/new.py”，第4行，在
导入nltk
文件“/usr/local/lib/python2.7/dist-packages/nltk-3.0.5-py2.7.egg/nltk/__init___.py”，第137行，in
从nltk.stem导入*
文件“/usr/local/lib/python2.7/dist packages/nltk-3.0.5-py2.7.egg/nltk/stem/_init__.py”，第29行，in
从nltk.stem.snowball导入SnowballStemmer
文件“/usr/local/lib/python2.7/dist packages/nltk-3.0.5-py2.7.egg/nltk/stem/snowball.py”，第25行，in
从nltk.stem导入porter
导入错误：无法导入名称

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几天前，我的nltk工作正常，我没有更新或更改任何内容，我还安装了所有nltk数据。

在nltk中使用Porter stemmer的惯用用法（请参阅）是：

>>> from nltk.stem import PorterStemmer
>>> porter = PorterStemmer()
>>> sent = 'I went on wild geese chases'
>>> porter.stem(sent)
u'I went on wild geese chas'

注意：那

PorterStemmer

不能很好地处理不规则复数

看看：