corpora is a group presenting multiple collections of text documents. a single collection is called corpus. one such famous corpus is the gutenberg corpus which contains some 25,000 free electronic books, hosted at http://www.gutenberg.org/. in the below example we access the names of only those files from the corpus which are plain text with filename ending as .txt.

from nltk.corpus import gutenberg
fields = gutenberg.fileids()

print(fields)

when we run the above program, we get the following output −

[austen-emma.txt', austen-persuasion.txt', austen-sense.txt', bible-kjv.txt', 
blake-poems.txt', bryant-stories.txt', burgess-busterbrown.txt',
carroll-alice.txt', chesterton-ball.txt', chesterton-brown.txt', 
chesterton-thursday.txt', edgeworth-parents.txt', melville-moby_dick.txt',
milton-paradise.txt', shakespeare-caesar.txt', shakespeare-hamlet.txt',
shakespeare-macbeth.txt', whitman-leaves.txt']

accessing raw text

we can access the raw text from these files using sent_tokenize function which is also available in nltk. in the below example we retrieve the first two paragraphs of the blake poen text.

from nltk.tokenize import sent_tokenize
from nltk.corpus import gutenberg

sample = gutenberg.raw("blake-poems.txt")

token = sent_tokenize(sample)

for para in range(2):
    print(token[para])

when we run the above program we get the following output −

[poems by william blake 1789]

 
songs of innocence and of experience
and the book of thel


 songs of innocence
 
 
 introduction
 
 piping down the valleys wild,
   piping songs of pleasant glee,
 on a cloud i saw a child,
   and he laughing said to me:
 
 "pipe a song about a lamb!"
so i piped with merry cheer.