[R] functions of functions
Robin Hankin
r.hankin at noc.soton.ac.uk
Mon May 9 09:54:38 CEST 2005
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
]
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
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