Difference between tokenize.fit_on_text
, tokenize.text_to_sequence
and word embeddings
?
Tried to search on various platforms but didn't get a suitable answer.
Tokenization—a fundamental process for natural language processing—strips a string into individual units. Or, in this case, text into individual words. Therefore, when the word embedding model is created, it forms a relational model between the words of a corpus, not phrases or concepts.
The Tokenizer class of Keras is used for vectorizing a text corpus. For this either, each text input is converted into integer sequence or a vector that has a coefficient for each token in the form of binary values.
When running a Word2Vec model, you might find it useful to tokenize your text. Tokenizing text converts strings into tokens, then stores the tokenized text into a single column, making it easier for additional processing.
texts_to_sequences( texts. ) Transforms each text in texts to a sequence of integers. Only top num_words-1 most frequent words will be taken into account.
Word embeddings is a way of representing words such that words with the same/similar meaning have a similar representation. Two commonly used algorithms that learn word embedding are Word2Vec and GloVe.
Note that word embeddings can also be learnt from scratch while training your neural network for text processing, on your specific NLP problem. You can also use transfer learning; in this case, it would mean to transfer the learned representation of the words from huge datasets on your problem.
As for the tokenizer(I assume it's Keras that we're speaking of), taking from the documentation:
tokenize.fit_on_text()
--> Creates the vocabulary index based on word frequency. For example, if you had the phrase "My dog is different from your dog, my dog is prettier", word_index["dog"] = 0
, word_index["is"] = 1
(dog appears 3 times, is appears 2 times)
tokenize.text_to_sequence()
--> Transforms each text into a sequence of integers. Basically if you had a sentence, it would assign an integer to each word from your sentence. You can access tokenizer.word_index()
(returns a dictionary) to verify the assigned integer to your word.
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