首先,在wordnet中word和synset/concept是有区别的。
这里我们看到一个词可以有多种含义(即链接到多个概念):
>>> from nltk.corpus import wordnet as wn
>>> car = 'car'
>>> auto = 'automobile'
>>> wn.synsets(auto)
[Synset('car.n.01'), Synset('automobile.v.01')]
>>> wn.synsets(car)
[Synset('car.n.01'), Synset('car.n.02'), Synset('car.n.03'), Synset('car.n.04'), Synset('cable_car.n.01')]
在这种情况下,'automobile' 和 'car' 可以指代同一个 Synset('car.n.01'),如果是这样,那么它们没有下位/上位关系。
还有lemma 的概念会使事情复杂化,所以我们现在将跳过它。
假设您不是比较单词而是比较同义词,那么您可以简单地找到同义词的所有下位词,看看其他同义词是否出现在其中。
如果您要比较简单的单词,请参阅How to get all the hyponyms of a word/synset in python nltk and wordnet?
下面将展示如何比较同义词集。例如,我将使用“fruit”和“apple”,这比“automobile”和“car”更符合逻辑,因为“automobile”和“car”只有一个名词同义词集
>>> from nltk.corpus import wordnet as wn
>>>
>>> fruit = 'fruit'
>>> wn.synsets(fruit)
[Synset('fruit.n.01'), Synset('yield.n.03'), Synset('fruit.n.03'), Synset('fruit.v.01'), Synset('fruit.v.02')]
>>> wn.synsets(fruit)[0].definition()
u'the ripened reproductive body of a seed plant'
>>> fruit = wn.synsets(fruit)[0]
>>>
>>> apple = 'apple'
>>> wn.synsets(apple)
[Synset('apple.n.01'), Synset('apple.n.02')]
>>> wn.synsets(apple)[0].definition()
u'fruit with red or yellow or green skin and sweet to tart crisp whitish flesh'
>>> apple = wn.synsets(apple)[0]
>>>
下面,我们看到apple不在fruit的直接下义词中:
>>> fruit.hyponyms()
[Synset('accessory_fruit.n.01'), Synset('achene.n.01'), Synset('acorn.n.01'), Synset('aggregate_fruit.n.01'), Synset('berry.n.02'), Synset('buckthorn_berry.n.01'), Synset('buffalo_nut.n.01'), Synset('chokecherry.n.01'), Synset('cubeb.n.01'), Synset('drupe.n.01'), Synset('ear.n.05'), Synset('edible_fruit.n.01'), Synset('fruitlet.n.01'), Synset('gourd.n.02'), Synset('hagberry.n.01'), Synset('hip.n.05'), Synset('juniper_berry.n.01'), Synset('marasca.n.01'), Synset('may_apple.n.01'), Synset('olive.n.01'), Synset('pod.n.02'), Synset('pome.n.01'), Synset('prairie_gourd.n.01'), Synset('pyxidium.n.01'), Synset('quandong.n.02'), Synset('rowanberry.n.01'), Synset('schizocarp.n.01'), Synset('seed.n.01'), Synset('wild_cherry.n.01')]
>>>
>>> apple in fruit.hyponyms()
False
所以我们必须遍历所有的下位词,看看 apple 是否在其中一个中:
>>> hypofruits = set([i for i in fruit.closure(lambda s:s.hyponyms())])
>>> apple in hypofruits
True
你有它!为了完整起见:
>>> hyperapple = set([i for i in apple.closure(lambda s:s.hypernyms())])
>>> fruit in hyperapple
True
>>> hypoapple = set([i for i in apple.closure(lambda s:s.hyponyms())])
>>> fruit in hypoapple
False
>>> hyperfruit = set([i for i in fruit.closure(lambda s:s.hypernyms())])
>>> apple in hyperfruit
False