outer {base} | R Documentation |
The outer product of the arrays X
and Y
is the array
A
with dimension c(dim(X), dim(Y))
where element
A[c(arrayindex.x, arrayindex.y)]
= FUN(X[arrayindex.x], Y[arrayindex.y], ...)
.
outer(X, Y, FUN="*", ...) X %o% Y
X |
A vector or array. |
Y |
A vector or array. |
FUN |
a function to use on the outer products, it may be a quoted string. |
... |
optional arguments to be passed to FUN . |
FUN
must be a function (or the name of it) which expects at
least two arguments and which operates elementwise on arrays.
Where they exist, the [dim]names of X
and Y
will be
preserved.
%o%
is an alias for outer
(where FUN
cannot be changed from "*"
).
Jonathan Rougier
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
%*%
for usual (inner) matrix vector
multiplication;
kronecker
which is based on outer
.
x <- 1:9; names(x) <- x # Multiplication & Power Tables x %o% x y <- 2:8; names(y) <- paste(y,":",sep="") outer(y, x, "^") outer(month.abb, 1999:2003, FUN = "paste") ## three way multiplication table: x %o% x %o% y[1:3]