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Category: nltk

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nltk stemming

nltk tags

The module NLTK can automatically tag speech.
Given a sentence or paragraph, it can label words such as verbs, nouns and so on.

NLTK - speech tagging example


The example below automatically tags words with a corresponding class.


import nltk
from nltk.tokenize import PunktSentenceTokenizer

document = 'Whether you\'re new to programming or an experienced developer, it\'s easy to learn and use Python.'
sentences = nltk.sent_tokenize(document)
for sent in sentences:
print(nltk.pos_tag(nltk.word_tokenize(sent)))

Related course
Easy Natural Language Processing (NLP) in Python

This will output a tuple for each word:
speech-tagging
where the second element of the tuple is the class.
The meanings of these speech codes are shown in the table below:
nltk-speech-codes

We can filter this data based on the type of word:


import nltk
from nltk.corpus import state_union
from nltk.tokenize import PunktSentenceTokenizer

document = 'Today the Netherlands celebrates King\'s Day. To honor this tradition, the Dutch embassy in San Francisco invited me to'
sentences = nltk.sent_tokenize(document)

data = []
for sent in sentences:
data = data + nltk.pos_tag(nltk.word_tokenize(sent))

for word in data:
if 'NNP' in word[1]:
print(word)

which outputs:

speech tagging Speech tagging

The classes include past tense, present. Using this technique we can quickly derive meaning from a text.

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