matrix {base}

R Documentation

Matrices

Description

matrix creates a matrix from the given set of values.

as.matrix attempts to turn its argument into a matrix.

is.matrix tests if its argument is a (strict) matrix.

Usage

matrix(data = NA, nrow = 1, ncol = 1, byrow = FALSE, dimnames = NULL)
as.matrix(x)
is.matrix(x)

Arguments

data	an optional data vector.
nrow	the desired number of rows
ncol	the desired number of columns
byrow	logical. If FALSE (the default) the matrix is filled by columns, otherwise the matrix is filled by rows.
dimnames	A dimnames attribute for the matrix: a list of length 2.
x	an R object.

Details

If either of nrow or ncol is not given, an attempt is made to infer it from the length of data and the other parameter.

is.matrix returns TRUE if x is a matrix (i.e., it is not a data.frame and has a dim attribute of length 2) and FALSE otherwise.

See Also

data.matrix.

Examples

is.matrix(as.matrix(1:10))
data(warpbreaks)
!is.matrix(warpbreaks)# data.frame, NOT matrix!
str(warpbreaks)
str(as.matrix(warpbreaks))#using as.matrix.data.frame(.) method

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