Section 3 Matrix

3.1 Function

Example vector: x <- c(1:12)

Function	Explanation	Example
matrix	Create a matrix	matrix(data=x, nrow=4, ncol=3, byrow=TRUE)
as.matrix	Convert a collection of vectors into matrix	as.matrix(x)
is.matrix	Check if its argument is a (strict) matrix	is.matrix(x)
dim	Get the dimension of a matrix	dim(x)
dimnames	A dimnames attribute for the matrix, NULL or a list of length 2	dimnames(x)
rownames	The row names of the matrix	rownames(x)
colnames	The column names of the matrix	colnames(x)
cbind, rbind	Column or row bind vectors to create a matrix	cbind(x,x)
attributes	Attributes of a matrix	attributes(x)
data.matrix	Attempts to convert a dataframe to a numeric matrix	data.matrix(x)

3.2 Example

?matrix

x <- c(1:12)
x
is.matrix(x)

y <- as.matrix(x)
y
is.matrix(y)
dim(y)
dimnames(y)

u <- matrix(data=x, nrow=4, ncol=3)
u

v <- x
dim(v) <- c(4, 3)
v

z <- matrix(data=x, nrow=4, ncol=3, byrow=TRUE)
z
is.matrix(z)
dim(z)
dimnames(z)

dimnames(z) <- list(LETTERS[1:4], letters[1:3])
dimnames(z)
attributes(z)

str(z)

rownames(z)
colnames(z)

rbind(x,x)
cbind(x,x)