python – 如何在NLTK的Wordnet中检索目标synset的反义词synset？

我已成功通过其他语义关系检索连接到基本synset的同义词集,如下所示：

 wn.synset('good.a.01').also_sees()
 Out[63]: 
 [Synset('best.a.01'),
 Synset('better.a.01'),
 Synset('favorable.a.01'),
 Synset('good.a.03'),
 Synset('obedient.a.01'),
 Synset('respectable.a.01')]

wn.synset('good.a.01').similar_tos()
Out[64]: 
[Synset('bang-up.s.01'),
 Synset('good_enough.s.01'),
 Synset('goodish.s.01'),
 Synset('hot.s.15'),
 Synset('redeeming.s.02'),
 Synset('satisfactory.s.02'),
 Synset('solid.s.01'),
 Synset('superb.s.02'),
 Synset('well-behaved.s.01')]

然而,反义词关系似乎不同.我设法检索连接到我的基本synset的引理,但无法检索实际的synset,如下所示：

wn.synset('good.a.01').lemmas()[0].antonyms()
Out[67]: [Lemma('bad.a.01.bad')]

如何通过antonymy连接到我的基本synset -wn.synset(‘good.a.01’)来获取synset而不是引理？ TIA

解决方法:

出于某种原因,WordNet在引理级别而不是Synset(参见http://wordnetweb.princeton.edu/perl/webwn?o2=&o0=1&o8=1&o1=1&o7=&o5=&o9=&o6=&o3=&o4=&s=good&i=8&h=00001000000000000000000000000000#c)索引反义关系,因此问题是Synsets和Lemmas是否具有多对多或一对一的关系.

在含糊不清的单词,一个含义很多的单词的情况下,我们在String-to-Synset之间有一对多的关系,例如

>>> wn.synsets('dog')
[Synset('dog.n.01'), Synset('frump.n.01'), Synset('dog.n.03'), Synset('cad.n.01'), Synset('frank.n.02'), Synset('pawl.n.01'), Synset('andiron.n.01'), Synset('chase.v.01')]

在一个含义/概念,多个表示的情况下,我们在Synset-to-String(其中String指引理名称)之间具有一对多关系：

>>> dog = wn.synset('dog.n.1')
>>> dog.definition()
u'a member of the genus Canis (probably descended from the common wolf) that has been domesticated by man since prehistoric times; occurs in many breeds'
>>> dog.lemma_names()
[u'dog', u'domestic_dog', u'Canis_familiaris']

注意：到目前为止,我们正在比较String和Synsets之间的关系,而不是Lemmas和Synsets.

“可爱”的东西是Lemma和String有一对一的关系：

>>> wn.synsets('dog')
[Synset('dog.n.01'), Synset('frump.n.01'), Synset('dog.n.03'), Synset('cad.n.01'), Synset('frank.n.02'), Synset('pawl.n.01'), Synset('andiron.n.01'), Synset('chase.v.01')]
>>> wn.synsets('dog')[0]
Synset('dog.n.01')
>>> wn.synsets('dog')[0].definition()
u'a member of the genus Canis (probably descended from the common wolf) that has been domesticated by man since prehistoric times; occurs in many breeds'
>>> wn.synsets('dog')[0].lemmas()
[Lemma('dog.n.01.dog'), Lemma('dog.n.01.domestic_dog'), Lemma('dog.n.01.Canis_familiaris')]
>>> wn.synsets('dog')[0].lemmas()[0]
Lemma('dog.n.01.dog')
>>> wn.synsets('dog')[0].lemmas()[0].name()
u'dog'

Lemma对象的_name属性返回unicode字符串,而不是列表.从代码点：https://github.com/nltk/nltk/blob/develop/nltk/corpus/reader/wordnet.py#L202和https://github.com/nltk/nltk/blob/develop/nltk/corpus/reader/wordnet.py#L444

看起来Lemma与Synset有一对一的关系.来自于https://github.com/nltk/nltk/blob/develop/nltk/corpus/reader/wordnet.py#L220的docstring：

Lemma attributes, accessible via methods with the same name::

• name: The canonical name of this lemma.
• synset: The synset that this lemma belongs to.
• syntactic_marker: For adjectives, the WordNet string identifying the
  syntactic position relative modified noun. See:
  07004
  For all other parts of speech, this attribute is None.
  
• count: The frequency of this lemma in wordnet.

所以我们可以这样做,并以某种方式知道每个Lemma对象只会返回1个synset：

>>> wn.synsets('dog')[0].lemmas()[0]
Lemma('dog.n.01.dog')
>>> wn.synsets('dog')[0].lemmas()[0].synset()
Synset('dog.n.01')

假设您正在尝试进行一些情绪分析,并且您需要WordNet中每个形容词的反义词,您可以轻松地接受反义词的Synsets：

>>> from nltk.corpus import wordnet as wn
>>> all_adj_in_wn = wn.all_synsets(pos='a')
>>> def get_antonyms(ss):
...     return set(chain(*[[a.synset() for a in l.antonyms()] for l in ss.lemmas()]))
...
>>> for ss in all_adj_in_wn:
...     print ss, ':', get_antonyms(ss)
... 
Synset('unable.a.01') : set([Synset('unable.a.01')])

标签：wordnet,python,nlp,nltk,lemmatization
来源： https://codeday.me/bug/20191008/1873741.html