Equivalent of rowsum function for Matrix-class (dgCMatrix)

问题

For the base R matrix class we have the rowsum function, which is very fast for computing column sums across groups of rows.

Is there an equivalent function or approach implemented in the Matrix-package?

I'm particularly interested in a fast alternative to rowsum for large dgCMatrix-objects (i.e. millions of rows, but roughly 95% sparse).

回答1:

I know this is an old question, but Matrix::rowSums might be the function you are looking for.

来源：https://stackoverflow.com/questions/51025979/equivalent-of-rowsum-function-for-matrix-class-dgcmatrix