Robin Hankin wrote:
Hello Uwe
thanks for this. Unfortunately it doesn't quite do what I want:
R> x <- c(0.3,0.3,0.5)
R> f(c("sin","cos"),1:2,x)
1] 1.266795
Warning messages:
1: longer object length
is not a multiple of shorter object length in: x + int
2: number of rows of result
is not a multiple of vector length (arg 1) in: cbind(foo, x + int)
R>
[
I need
R> sin(x+1) + cos(x+2)
[1] 0.2972822 0.2972822 0.1963514
]
I see, now the problem is much clearer, so what about:
f <- function(foo, int, x){
lf <- length(foo)
li <- length(int)
l <- max(lf, li)
if(l > lf) foo <- rep(foo, length = l)
else if(l > li) int <- rep(int, length = l)
values <- mapply(function(foo, int)
do.call(foo, list(x+int)), foo, int)
return(rowSums(values))
}
Uwe
best wishes
Robin
On May 9, 2005, at 08:34 am, Uwe Ligges wrote:
Robin Hankin wrote:
Hi
I have an application where my difficulty boils down to not
being able to define a function f() with the following properties:
f("sin",0:2,x) #returns sin(x+0) + sin(x+1) + sin(x+2)
f(c("sin","cos"), 1:2,x) #returns sin(x+1) + cos(x+2)
f(c("sin","cos","exp"),3,x) #returns sin(x+3) + cos(x+3) + exp(x+3)
anyone?
Not really nice, but hopefully works:
f <- function(foo, int, x){
# too lazy to think myself about recycling:
X <- cbind(foo, x + int)
# mapply-ing over both columns
values <- mapply(function(foo, x) do.call(foo, list(x)),
X[,1], as.integer(X[,2]))
# caculating the sum:
return(sum(values))
}
Uwe
--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre, Southampton
European Way, Southampton SO14 3ZH, UK
tel 023-8059-7743
______________________________________________
[email protected] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
