Megh Dal wrote:
Dear falks, here I have written following function :
fn <- Vectorize(function(x = 1:3, y = 3:6) {
x <- matrix(x, nrow=1)
y <- matrix(y, ncol=1)
dat <- apply(x, 2, function(xx) {
apply(y, 1, function(yy) {
return(xx + yy) } ) })
return(dat)}, SIMPLIFY = TRUE)
If I run this function, I got some warning message, even format of the returned
object is not correct, for example :
fn(x = 1:3, y = 3:7)
[1] 4 6 8 7 9
Warning message:
In mapply(FUN = function (x = 1:3, y = 3:6) :
longer argument not a multiple of length of shorter
However if I run individual line of codes like :
x <- 1:3; y = 3:7
x <- matrix(x, nrow=1)
y <- matrix(y, ncol=1)
dat <- apply(x, 2, function(xx) {
+ apply(y, 1, function(yy) {
+ return(xx + yy) } ) })
dat
[,1] [,2] [,3]
[1,] 4 5 6
[2,] 5 6 7
[3,] 6 7 8
[4,] 7 8 9
[5,] 8 9 10
I get exactly what I want. Where I am making fault?
I think you don't understand what Vectorize is trying to do. It is
basically a way to run a loop, calling your function with each matching
pair of x and y values, i.e. x=1, y=3 in the first call, then x=2 y=4 in
the second, etc. The warning comes because you have three x values and
five y values, so it will repeat the 1st two x values -- but it warns
you that's likely not what you intended.
Duncan Murdoch
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