Linguistics
Expanding the "Librarian": Lexical Relations in NLTK
While Gensim uses math and spaCy uses statistical brains, NLTK relies on WordNet. This allows it to navigate precise "nyms"—the linguistic categories that define how words relate to one another.
1. The "Is-A" Hierarchy (Taxonomy)
- Hypernyms: The broader, "umbrella" term.
Example: "Fruit" is the hypernym of "Apple." - Hyponyms: The specific sub-type.
Example: "Salmon" is a hyponym of "Fish."
2. The "Has-A" Hierarchy (Parts and Wholes)
- Meronyms: A part of a whole.
Example: "Wheel" is a meronym of "Bicycle." - Holonyms: The whole entity that contains parts.
Example: "Keyboard" is a holonym of "Escape Key."
3. Meanings and Opposites
- Synonyms: Words with identical or near-identical meanings.
Example: "Purchase" and "Buy." - Antonyms: Words with opposite meanings.
Example: "Victory" and "Defeat."
Library Comparison Table
| Feature | NLTK | spaCy | Gensim |
|---|---|---|---|
| Logic | Human-defined Dictionary | Pre-trained Statistical Brain | Neural Network Math |
| Best For | Synonyms & Part-of logic | Similarity scores & Speed | Finding hidden patterns |
| Weakness | Doesn't understand slang | Can confuse opposites | Needs huge amounts of data |