matrixStats (version 1.2.0)

rowTabulates: Tabulates the values in a matrix by row (column).

Description

Tabulates the values in a matrix by row (column).

Usage

rowTabulates(x, rows = NULL, cols = NULL, values = NULL, ...,
  useNames = TRUE)
colTabulates(x, rows = NULL, cols = NULL, values = NULL, ...,
  useNames = TRUE)

Value

Returns a NxJ (KxJ) matrix where N (K) is the number of row (column) vectors tabulated and J is the number of values counted.

Arguments

x

An integer, a logical, or a raw NxK matrix.

rows

A vector indicating subset of rows to operate over. If NULL, no subsetting is done.

cols

A vector indicating subset of columns to operate over. If NULL, no subsetting is done.

values

An vector of J values of count. If NULL, all (unique) values are counted.

...

Not used.

useNames

If TRUE (default), names attributes of the result are set, otherwise not.

Author

Henrik Bengtsson

Details

An alternative to these functions, is to use table(x, row(x)) and table(x, col(x)), with the exception that the latter do not support the raw data type. When there are no missing values in x, we have that all(rowTabulates(x) == t(table(x, row(x)))) and all(colTabulates(x) == t(table(x, col(x)))). When there are missing values, we have that all(rowTabulates(x) == t(table(x, row(x), useNA = "always")[, seq_len(nrow(x))])) and all(colTabulates(x) == t(table(x, col(x), useNA = "always")[, seq_len(ncol(x))])).

Examples

x <- matrix(1:5, nrow = 10, ncol = 5)
print(x)
print(rowTabulates(x))
print(colTabulates(x))
# Count only certain values
print(rowTabulates(x, values = 1:3))


y <- as.raw(x)
dim(y) <- dim(x)
print(y)
print(rowTabulates(y))
print(colTabulates(y))