Search notes:
R function: is.matrix
is.matrix(obj) returns true if
obj is a
vector and has a
dim attribute whose length is 2:
vec <- c(1, 2, 3, 4, 5, 6, 7, 8);
is.matrix(vec);
#
# FALSE
dim(vec) <- c(8);
is.matrix(vec);
#
# FALSE
dim(vec) <- c(4, 2);
is.matrix(vec);
#
# TRUE
dim(vec) <- c(2, 2, 2);
is.matrix(vec);
#
# FALSE
An object that is created with
matrix is, of course, a matrix:
m = matrix( c( 1, 2, 3, 4,
11, 22, 33, 44,
111, 222, 333, 444,
1111,2222,3333,4444),
nrow=4,
ncol=4)
is.matrix(m)
# [1] TRUE