从文本文件中选择少于 280 个字符的随机句子

Question

I am working on a project where I want to read a large text file, randomly select a full sentence from that file. If that file sentence is less 280 characters or less, print that file out. if not select another sentence until it finds a sentence that is less than 280 characters. Using nltk I am able to break down the text into individual sentences, select one randomly and count the characters.

import nltk.data
import random

tokenizer = nltk.data.load('tokenizers/punkt/english.pickle')

fp = open("test.txt")

data = fp.read()

tok = tokenizer.tokenize(data); #breaks into sentences 

newTok = random.choice(tok) #selects random sentence 

length = len(newTok) #gives amount of characters in random sentence

I am now trying to work create a while loop that will test if a sentence is less than 280 chcaracters to print it, and if it is not will select another sentence randomly to test

while length < 280:  # while length of sentence is less than 280

      print "length of sentence = ", length # do this 
      print newTok # do this 
      break #stops loop

      else: 
          print length, " is too long" 

but this is giving me an invalid syntax error on else, but also I think will not iterate again to find another sentence.

Any suggestions would be great.

Answer 1

After getting the list of tokens:

tok = tokenizer.tokenize(data); #breaks into sentences 

...the rest is a one-liner:

newTok = random.choice([x for x in tok if len(x)<280])

Note the use of a list comprehension with an if to narrow the items from the token list to those whose length is less than 280 characters.