LemmInflect

0.2.3 verified Fri May 01 auth: no python maintenance

A Python module for English lemmatization and inflection (generating inflected forms from lemmas). It provides a lookup-based and rule-based approach for verbs, nouns, adjectives, and adverbs. Current version: 0.2.3 (last release April 2022). Release cadence is low.

pip install lemminflect

Common errors

error lemminflect doesn't handle 'ran' as past tense of 'run' ↓

cause LemmInflect relies heavily on a lookup dictionary. Some irregular forms may be missing or have gaps.

fix

Use fallback to a rule-based lemmatizer (e.g., NLTK's WordNetLemmatizer) or add custom mappings.

error getInflection('fly', 'VBD') returns an empty tuple ↓

cause The word lemma 'fly' is stored but the past tense form 'flew' might be missing from the inflections dictionary in some cases.

fix

Check if the lemma exists: getLemma('fly', 'VB') should return 'fly'. Then try getInflection with the correct lemma. If still empty, consider using getAllInflections('fly') to see all known forms.

Warnings

gotcha POS tags must be in Penn Treebank format (e.g., 'VB', 'VBD', 'NN', 'JJ', etc.) not Universal Dependencies. Using wrong tags returns empty results silently. ↓

fix Use PTB tags: VB (verb base), VBD (past), VBG (gerund), VBN (past participle), VBP (present non-3rd), VBZ (present 3rd), NN (noun), NNS (plural noun), JJ (adjective), JJR (comparative), JJS (superlative), RB (adverb), RBR (comparative adverb), RBS (superlative adverb).

gotcha The function returns an empty list/tuple if the word is unknown or the lemma cannot be found. It does not raise exceptions. ↓

fix Always check the return value: e.g., result = getLemma('word', 'NN'); if result: ... else: handle unknown.

deprecated The module is not actively maintained; last release 0.2.3 was in 2022. No support for newer spaCy versions or Python 3.12+ out of the box. ↓

fix Consider using spaCy's built-in lemmatizer or the 'simplemma' library for active development.

Imports

getLemma
```
from lemminflect import getLemma
```
Direct import of the lemmatization function.
getInflection
```
from lemminflect import getInflection
```
Direct import of the inflection function.
getAllInflections
```
from lemminflect import getAllInflections
```
Import all inflections (returns dict of all forms).
getAllLemmas
```
from lemminflect import getAllLemmas
```
Import all lemmas (returns dict of all lemma forms).
isTagBaseForm
```
from lemminflect import isTagBaseForm
```
Check if a tag corresponds to the base form of a word.

Quickstart

Basic lemmatization and inflection using Penn Treebank POS tags.

from lemminflect import getLemma, getInflection

# Lemmatize a word
lemma = getLemma('flies', 'VERB')
print(f"Lemma: {lemma}")  # Output: 'fly'

# Inflect a lemma to a specific form
inflected = getInflection('fly', 'VBD')
print(f"Inflected: {inflected}")  # Output: ('flew',)

# Note: POS tags are Penn Treebank-like (NN, VB, JJ, etc.)