Rejo Varghese Rejo Varghese - 3 months ago 31
Python Question

How to split a string on commas or periods in nltk

I want to separate a string on commas and/or periods in nltk. I've tried with

sent_tokenize()
but it separates only on periods.

I've also tried this code

from nltk.tokenize.punkt import PunktSentenceTokenizer, PunktLanguageVars
ex_sent = "This is an example showing sentence filtration.This is how it is done, in case of Python I want to learn more. So, that i can have some experience over it, by it I mean python."
class CommaPoint(PunktLanguageVars):
sent_end_chars = ('.','?','!',',')
tokenizer = PunktSentenceTokenizer(lang_vars = CommaPoint())
n_w=tokenizer.tokenize(ex_sent)
print n_w


The output for the code above is

['This is an example showing sentence filtration.This is how it is done,' 'in case of Python I want to learn more.' 'So,' 'that i can have some experience over it,' 'by it I mean python.\n']


When I try to give '.' without any space it is taking it as a word

I want the output as

['This is an example showing sentence filtration.' 'This is how it is done,' 'in case of Python I want to learn more.' 'So,' 'that i can have some experience over it,' 'by it I mean python.']


image of the above written code

Answer

How about something simpler with re:

>>> import re
>>> sent = "This is an example showing sentence filtration.This is how it is done, in case of Python I want to learn more. So, that i can have some experience over it, by it I mean python."
>>> re.split(r'[.,]', sent)
['This is an example showing sentence filtration', 'This is how it is done', ' in case of Python I want to learn more', ' So', ' that i can have some experience over it', ' by it I mean python', '']

To keep the delimiter, you can use group:

>>> re.split(r'([.,])', sent)
['This is an example showing sentence filtration', '.', 'This is how it is done', ',', ' in case of Python I want to learn more', '.', ' So', ',', ' that i can have some experience over it', ',', ' by it I mean python', '.', '']