wn.morphy¶

A simple English lemmatizer that finds and removes known suffixes.

Initialized and Uninitialized Morphy¶

There are two ways of using Morphy in Wn: initialized and uninitialized.

Unintialized Morphy is a simple callable that returns lemma candidates for some given wordform. That is, the results might not be valid lemmas, but this is not a problem in practice because subsequent queries against the database will filter out the invalid ones. This callable is obtained by creating a Morphy object with no arguments:

>>> from wn import morphy
>>> m = morphy.Morphy()

As an uninitialized Morphy cannot predict which lemmas in the result are valid, it always returns the original form and any transformations it can find for each part of speech:

>>> m('lemmata', pos='n')  # exceptional form
{'n': {'lemmata'}}
>>> m('lemmas', pos='n')   # regular morphology with part-of-speech
{'n': {'lemma', 'lemmas'}}
>>> m('lemmas')            # regular morphology for any part-of-speech
{None: {'lemmas'}, 'n': {'lemma'}, 'v': {'lemma'}}
>>> m('wolves')            # invalid forms may be returned
{None: {'wolves'}, 'n': {'wolf', 'wolve'}, 'v': {'wolve', 'wolv'}}

This lemmatizer can also be used with a wn.Wordnet object to expand queries:

>>> import wn
>>> ewn = wn.Wordnet('ewn:2020')
>>> ewn.words('lemmas')
[]
>>> ewn = wn.Wordnet('ewn:2020', lemmatizer=morphy.Morphy())
>>> ewn.words('lemmas')
[Word('ewn-lemma-n')]

An initialized Morphy is created with a wn.Wordnet object as its argument. It then uses the wordnet to build lists of valid lemmas and exceptional forms (this takes a few seconds). Once this is done, it will only return lemmas it knows about:

>>> ewn = wn.Wordnet('ewn:2020')
>>> m = morphy.Morphy(ewn)
>>> m('lemmata', pos='n')  # exceptional form
{'n': {'lemma'}}
>>> m('lemmas', pos='n')   # regular morphology with part-of-speech
{'n': {'lemma'}}
>>> m('lemmas')            # regular morphology for any part-of-speech
{'n': {'lemma'}}
>>> m('wolves')            # invalid forms are pre-filtered
{'n': {'wolf'}}

In order to use an initialized Morphy lemmatizer with a wn.Wordnet object, it must be assigned to the object after creation:

>>> ewn = wn.Wordnet('ewn:2020')  # default: lemmatizer=None
>>> ewn.words('lemmas')
[]
>>> ewn.lemmatizer = morphy.Morphy(ewn)
>>> ewn.words('lemmas')
[Word('ewn-lemma-n')]

There is little to no difference in the results obtained from a wn.Wordnet object using an initialized or uninitialized Morphy object, but there may be slightly different performance profiles for future queries.

Default Morphy Lemmatizer¶

As a convenience, an uninitialized Morphy lemmatizer is provided in this module via the morphy member.

wn.morphy.morphy¶: A Morphy object created without a wn.Wordnet object.

The Morphy Class¶

class wn.morphy.Morphy(wordnet=None)¶

The Morphy lemmatizer class.

Objects of this class are callables that take a wordform and an optional part of speech and return a dictionary mapping parts of speech to lemmas. If objects of this class are not created with a wn.Wordnet object, the returned lemmas may be invalid.

Parameters: wordnet (Optional[wn.Wordnet]) – optional wn.Wordnet instance

Example

>>> import wn
>>> from wn.morphy import Morphy
>>> ewn = wn.Wordnet('ewn:2020')
>>> m = Morphy(ewn)
>>> m('axes', pos='n')
{'n': {'axe', 'ax', 'axis'}}
>>> m('geese', pos='n')
{'n': {'goose'}}
>>> m('gooses')
{'n': {'goose'}, 'v': {'goose'}}
>>> m('goosing')
{'v': {'goose'}}