How do you normalize the rows of a document term matrix in place in R?

Question

I have a DocumentTermMatrix named train_dtm and I want to normalize the frequency counts of the term frequencies in all the documents. The problem I am facing is that the resulting matrix should also be of type DocumentTermMatrix because I want to pass the normalized matrix to another method LDA of the TopicModels package in R.

Below is the method I am using:

docs_dtm <- DocumentTermMatrix(docs)

Now, I want the rows of the above documenttermmatrix to be normalized. I even tried adding the control parameter via

docs_dtm <- DocumentTermMatrix(docs, control=list(weighting = function(x) weightTf(x, normalize=TRUE)))

but the above call throws an error saying

Error in weightTf(x, normalize=TRUE): unused argument (normalize = TRUE)

I have written the method to normalize the values of train_dtm using apply() method but it does not return a matrix of type DocumentTermMatrix.

Is there another way to accomplish the above task?

Do you have a minimal working example? – Tyler Rinker Mar 31 '15 at 14:40 — Tyler Rinker, Mar 31 '15 at 14:40
Thanks for responding. I have pasted my code above. – London guy Mar 31 '15 at 14:44 — London guy, Mar 31 '15 at 14:44

score 0 · Answer 1 · answered Jun 12 '15 at 13:41

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Could you try passing the weighting argument directly, e.g.:

docs_dtm <- DocumentTermMatrix(docs, control = list(weighting = weightTf, normalize = TRUE))

answered Jun 12 '15 at 13:41

Joshua Rosenberg

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score 0 · Answer 2 · edited Dec 04 '18 at 15:26

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Normalize after creating the dtm:

docs_dtm_norm <- t(apply(docs_dtm, 1, function(x) x/sqrt(sum(x^2))))

edited Dec 04 '18 at 15:26

Bsquare ℬℬ

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answered Dec 04 '18 at 15:09

cpt. couteau

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How do you normalize the rows of a document term matrix in place in R?

2 Answers2