How to generate a list of antonyms for adjectives in WordNet using Python

Question

I want to do the following in Python (I have the NLTK library, but I'm not great with Python, so I've written the following in a weird pseudocode):

from nltk.corpus import wordnet as wn  #Import the WordNet library
for each adjective as adj in wn        #Get all adjectives from the wordnet dictionary
    print adj & antonym                #List all antonyms for each adjective 
once list is complete then export to txt file

This is so I can generate a complete dictionary of antonyms for adjectives. I think it should be doable, but I don't know how to create the Python script. I'd like to do it in Python as that's the NLTK's native language.

Answer 1

from nltk.corpus import wordnet as wn

for i in wn.all_synsets():
    if i.pos() in ['a', 's']: # If synset is adj or satelite-adj.
        for j in i.lemmas(): # Iterating through lemmas for each synset.
            if j.antonyms(): # If adj has antonym.
                # Prints the adj-antonym pair.
                print j.name(), j.antonyms()[0].name()

Note that there will be reverse duplicates.

[out]:

able unable
unable able
abaxial adaxial
adaxial abaxial
acroscopic basiscopic
basiscopic acroscopic
abducent adducent
adducent abducent
nascent dying
dying nascent
abridged unabridged
unabridged abridged
absolute relative
relative absolute
absorbent nonabsorbent
nonabsorbent absorbent
adsorbent nonadsorbent
nonadsorbent adsorbent
absorbable adsorbable
adsorbable absorbable
abstemious gluttonous
gluttonous abstemious
abstract concrete
...

Answer 2

The following function uses WordNet to return a set of adjective-only antonyms for a given word:

from nltk.corpus import wordnet as wn

def antonyms_for(word):
    antonyms = set()
    for ss in wn.synsets(word):
        for lemma in ss.lemmas():
            any_pos_antonyms = [ antonym.name() for antonym in lemma.antonyms() ]
            for antonym in any_pos_antonyms:
                antonym_synsets = wn.synsets(antonym)
                if wn.ADJ not in [ ss.pos() for ss in antonym_synsets ]:
                    continue
                antonyms.add(antonym)
    return antonyms

Usage:

print(antonyms_for("good"))