dtm_colsums: Column sums and Row sums for document term matrices

In udpipe: Tokenization, Parts of Speech Tagging, Lemmatization and Dependency Parsing with the 'UDPipe' 'NLP' Toolkit

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())

udpipe documentation built on Jan. 6, 2023, 5:06 p.m.