nlp8. Shortening stop word list in Python NLTK

In the previous program, the stop list S contained 127 words.

We remove the words 'then' and 'now' using set operations so its new size is 125. Even though S changed from the list to set, the rest of the program did not have to change.

# nlp8.py
from __future__ import print_function, division
from nltk.corpus import stopwords
from nltk.tokenize import word_tokenize
lines = """Dr. Brown gave a speech. I'd wish I knew then
what I know now. Finally, he praised Python! At 8 o'clock,
he went home.""" 
S = stopwords.words("english")
nS = ['then','now']
S = set(S)-set(nS)
t = '\t'
A = word_tokenize(lines.lower())
for a in A:
    if a not in S:
        print(t,a)

#         dr.
#         brown
#         gave
#         speech
#         .
#         'd
#         wish
#         knew
#         then
#         know
#         now
#         .
#         finally
#         ,
#         praised
#         python
#         !
#         8
#         o'clock
#         ,
#         went
#         home
#         .