您如何规范化R中适当的文档术语矩阵的行？

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?

Answer 1

您能否尝试直接传递weighting参数，例如：

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

Answer 2

创建dtm后进行标准化：

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