python - 使用 NLTK for Python 训练用于情感分析的推文语料库

Question

我正在尝试使用 Python 的 NLTK 来训练自己的语料库进行情感分析。我有两个文本文件:一个包含 25K 条正面推文，每行分隔，另一个包含 25K 条负面推文。

I use this Stackoverflow article, method 2

当我运行此代码来创建语料库时:

import string
from itertools import chain

from nltk.corpus import stopwords
from nltk.probability import FreqDist
from nltk.classify import NaiveBayesClassifier as nbc
from nltk.corpus import CategorizedPlaintextCorpusReader
import nltk

mydir = 'C:\Users\gerbuiker\Desktop\Sentiment Analyse\my_movie_reviews'

mr = CategorizedPlaintextCorpusReader(mydir, r'(?!\.).*\.txt', cat_pattern=r'(neg|pos)/.*', encoding='ascii')
stop = stopwords.words('english')
documents = [([w for w in mr.words(i) if w.lower() not in stop and w.lower() not in string.punctuation], i.split('/')[0]) for i in mr.fileids()]

word_features = FreqDist(chain(*[i for i,j in documents]))
word_features = word_features.keys()[:100]

numtrain = int(len(documents) * 90 / 100)
train_set = [({i:(i in tokens) for i in word_features}, tag) for tokens,tag in documents[:numtrain]]
test_set = [({i:(i in tokens) for i in word_features}, tag) for tokens,tag  in documents[numtrain:]]

classifier = nbc.train(train_set)
print nltk.classify.accuracy(classifier, test_set)
classifier.show_most_informative_features(5)

我收到错误消息:

C:\Users\gerbuiker\Anaconda\python.exe "C:/Users/gerbuiker/Desktop/Sentiment Analyse/CORPUS_POS_NEG/CreateCorpus.py"
Traceback (most recent call last):
  File "C:/Users/gerbuiker/Desktop/Sentiment Analyse/CORPUS_POS_NEG/CreateCorpus.py", line 23, in <module>
    documents = [([w for w in mr.words(i) if w.lower() not in stop and w.lower() not in string.punctuation], i.split('/')[0]) for i in mr.fileids()]
  File "C:\Users\gerbuiker\AppData\Roaming\Python\Python27\site-packages\nltk\corpus\reader\util.py", line 336, in iterate_from
    assert self._len is not None
AssertionError

Process finished with exit code 1

有人知道如何解决这个问题吗？

Answer 1

我不是 100% 肯定，因为我目前不在 Windows 机器上测试这个，但我认为可能让您感兴趣的是 @alvas 原始示例中的路径斜杠方向与您的路径斜杠方向之间的差异适应windows。

具体来说，您使用:'C:\Users\gerbuiker\Desktop\Sentiment Analyse\my_movie_reviews'，而他的示例使用'/home/alvas/my_movie_reviews'。在大多数情况下，这很好，但您尝试重新使用他的 cat_pattern 正则表达式:r'(neg|pos)/.*' 它将匹配中的斜杠他的道路，但拒绝你的道路。