Question

我不熟悉NLTK（http://www.nltk.org/）和python。我希望使用NLTK python库，但使用BNC作为语料库。我不相信这个语料库是通过NLTK数据下载分发的。有没有办法导入NLTK使用的BNC语料库。如果是这样，怎么样？我找到了一个名为BNCCorpusReader的函数，但不知道如何使用它。此外，在BNC网站，我能够下载语料库（http://ota.ox.ac.uk/desc/2554）。

http://www.nltk.org/api/nltk.corpus.reader.html?highlight=bnc#nltk.corpus.reader.BNCCorpusReader.word

更新

我尝试了entrophy的建议，但得到以下错误：

raise IOError('No such file or directory: %r' % _path)
OSError: No such file or directory: 'C:\\Users\\jason\\Documents\\NetBeansProjects\\DemoCollocations\\src\\Corpora\\bnc\\A\\A0\\A00.xml'

我在语料库中读取的代码：

bnc_reader = BNCCorpusReader(root="Corpora/bnc", fileids=r'[A-K]/\w*/\w*\.xml')

由语料库位于： C：\用户\杰森\文件\的NetBeansProjects \ DemoCollocations \ SRC \语料库\ BNC \

Answer 1

关于nltk用于配置提取的示例，请查看以下指南：A how-to guide by nltk on collocations extraction

就BNC语料库阅读器而言，所有信息都在文档中。

from nltk.corpus.reader.bnc import BNCCorpusReader
from nltk.collocations import BigramAssocMeasures, BigramCollocationFinder

# Instantiate the reader like this
bnc_reader = BNCCorpusReader(root="/path/to/BNC/Texts", fileids=r'[A-K]/\w*/\w*\.xml')

#And say you wanted to extract all bigram collocations and 
#then later wanted to sort them just by their frequency, this is what you would do.
#Again, take a look at the link to the nltk guide on collocations for more examples.

list_of_fileids = ['A/A0/A00.xml', 'A/A0/A01.xml']
bigram_measures = BigramAssocMeasures()
finder = BigramCollocationFinder.from_words(bnc_reader.words(fileids=list_of_fileids))
scored = finder.score_ngrams(bigram_measures.raw_freq)

print(scored)

输出结果如下：

[(('of', 'the'), 0.004902261167963723), (('in', 'the'),0.003554139346773699), 
 (('.', 'The'), 0.0034315828175746064), (('Gift', 'Aid'), 0.0019609044671854894), 
 ((',', 'and'), 0.0018996262025859428), (('for', 'the'), 0.0018383479379863962), ... ]

如果你想用分数对它们进行排序，你可以尝试这样的事情

sorted_bigrams = sorted(bigram for bigram, score in scored)

print(sorted_bigrams)

由于：

[('!', 'If'), ('!', 'Of'), ('!', 'Once'), ('!', 'Particularly'), ('!', 'Raising'), 
 ('!', 'YOU'), ('!', '‘'), ('&', 'Ealing'), ('&', 'Public'), ('&', 'Surrey'), 
 ('&', 'TRAINING'), ("'", 'SPONSORED'), ("'S", 'HOME'), ("'S", 'SERVICE'), ... ]

在NLTK使用英国国家语料库

1 个答案: