Getting a Corpus with Python

A corpus is a collection of text documents. A collection is called a corpus. One well-known corpus is the Gutenberg Corpus, which contains approximately 25,000 free e-books and is hosted at http://www.gutenberg.org/. In the following example, we only access the names of plain text files whose names end in .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 the Raw Text

We can access the raw text from these files using the sent_tokenize function, also available in nltk. In the example below, we retrieve the first two paragraphs of Blake’s poem.

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 will 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.