R: Column sums and Row sums for document term matrices

dtm_colsums {udpipe} | R Documentation

## Column sums and Row sums for document term matrices

### Description

Column sums and Row sums for document term matrices

### Usage

    dtm_colsums(dtm, groups)

    dtm_rowsums(dtm, groups)

### Arguments

`dtm` | an object returned by `document_term_matrix`
`groups` | optionally, a list with column/row names or column/row indexes of the `dtm` which should be combined by taking the sum over the rows or columns of these. See the examples

### Value

Returns either a vector in case argument `groups` is not provided or a sparse matrix of class `dgCMatrix` in case argument `groups` is provided

- in case `groups` is not provided: a vector of row/column sums with corresponding names

- in case `groups` is provided: a sparse matrix containing summed information over the groups of rows/columns

### Examples

    x <- data.frame(
     doc_id = c(1, 1, 2, 3, 4),
     term = c("A", "C", "Z", "X", "G"),
     freq = c(1, 5, 7, 10, 0))
    dtm <- document_term_matrix(x)
    x <- dtm_colsums(dtm)
    x
    x <- dtm_rowsums(dtm)
    head(x)

    ##
    ## Grouped column summation
    ##
    x <- list(doc1 = c("aa", "bb", "aa", "b"), doc2 = c("bb", "bb", "BB"))
    dtm <- document_term_matrix(x)
    dtm
    dtm_colsums(dtm, groups = list(combinedB = c("b", "bb"), combinedA = c("aa", "A")))
    dtm_colsums(dtm, groups = list(combinedA = c("aa", "A")))
    dtm_colsums(dtm, groups = list(
      combinedB = grep(pattern = "b", colnames(dtm), ignore.case = TRUE, value = TRUE),
      combinedA = c("aa", "A", "ZZZ"),
      test      = character()))
    dtm_colsums(dtm, groups = list())

    ##
    ## Grouped row summation
    ##
    x <- list(doc1 = c("aa", "bb", "aa", "b"),
              doc2 = c("bb", "bb", "BB"),
              doc3 = c("bb", "bb", "BB"),
              doc4 = c("bb", "bb", "BB", "b"))
    dtm <- document_term_matrix(x)
    dtm
    dtm_rowsums(dtm, groups = list(doc1 = "doc1", combi = c("doc2", "doc3", "doc4")))
    dtm_rowsums(dtm, groups = list(unknown = "docUnknown", combi = c("doc2", "doc3", "doc4")))
    dtm_rowsums(dtm, groups = list())

[Package udpipe version 0.8.6 Index]