is.na() Methods for 'Matrix' Objects

Description

Methods for function is.na() for all Matrices (objects extending the Matrix class):

x = "denseMatrix"

returns a "nMatrix" object of same dimension as x, with TRUE's whenever x was NA.

x = "sparseMatrix"

ditto.

Usage

## S4 method for signature 'sparseMatrix':
is.na(x)

Arguments

See Also

NA, is.na; nMatrix, denseMatrix, sparseMatrix.

Examples

M <- Matrix(1:6, nrow=4, ncol=3,
       dimnames = list(c("a", "b", "c", "d"), c("A", "B", "C")))
stopifnot(all(!is.na(M)))
M[2:3,2] <- NA
is.na(M)

A <- spMatrix(10,20, i = c(1,3:8),
                     j = c(2,9,6:10),
                     x = 7 * (1:7))
stopifnot(all(!is.na(A)))
A[2,3] <- A[1,2] <- A[5, 5:9] <- NA
inA <- is.na(A)
stopifnot(sum(inA) == 1+1+5)