R: Combine columns in matrix having same column name

Question

I have a large document-Term matrix.

I want to combine columns which with the same column name.

I have found someone asked the same problem and had work solution. Combine columns in matrix having same column name

I have tried using the answer to do.

But R returns an error message to me.

Error: cannot allocate vector of size 49.3 Gb

#my large matrix
tf_mat <- as.matrix(dtm_title) %>%
          cbind(as.matrix(dtm_abstract)) %>%
          cbind(as.matrix(dtm_claim)) 

#Combine columns with same column name.
nms <- colnames(tf_mat)
tf_mat %*% sapply(unique(nms),"==", nms)

Error: cannot allocate vector of size 49.3 Gb

Is there any way to solve it? Or is there any other solution?

There are lot of posts about solving the error you are facing. For example, [1](https://stackoverflow.com/questions/5171593/r-memory-management-cannot-allocate-vector-of-size-n-mb) , [2](https://stackoverflow.com/questions/10917532/r-memory-allocation-error-cannot-allocate-vector-of-size-75-1-mb) or [3](https://stackoverflow.com/questions/44169978/error-cannot-allocate-vector-of-size-1000-0-mb-r) . — Ronak Shah, Aug 22 '17 at 03:26

score 0 · Answer 1 · answered Aug 22 '17 at 06:15

Thanks for all of your opinion.

I have tried use another way from Combine columns in matrix having same column name.

I think it's more suitable for my case, and don't take lot of time to execute.

nms <- colnames(tf_mat)
tf_mat_bind <- sapply(unique(nms), function(i)rowSums(tf_mat[, nms==i, drop=FALSE]))

R: Combine columns in matrix having same column name

1 Answers1