Hello,
If in faux we ?force the return value, the bug is gone.
faux <- function(c) {
f <- function (x) get(paste0(c,"gamma"))(x,k,scale=theta)
force(f)
f
}
Hope this helps,
Rui Barradas
Em 05-06-2013 07:13, Michael Weylandt escreveu:
On Jun 5, 2013, at 3:53, Julio Sergio <julioser...@gmail.com> wrote:
I want to generate specific gamma distribution functions, given fixed
parameters.
This is I have k, and theta, say
k <- 32.2549 # shape
theta <- 26.32809 # scale
# I have an auxiliary function that produces funcions according to
# a given character (this is to have either dgamma, pgamma or qgamma)
# for the specific parameters given above:
faux <- function(c) {
function (x) get(paste0(c,"gamma"))(x,k,scale=theta)
}
# So I can have, for instance, dgamma, and pgamma with
dff <- faux("d")
pff <- faux("p")
dff(1000)
## [1] 0.001433138
pff(1000)
## [1] 0.844305
Now, if I try to produce both functions in one shot with lapply, the thing
doesn't work, see
ffs <- lapply(c("d", "p"), faux)
ffs[[1]](1000)
## [1] 0.844305
ffs[[2]](1000)
## [1] 0.844305
The two produced functions are the very same and correspond to pgamma!!
Maybe I'm missing something. Do you have any idea?
I think you are hitting a bit of strangeness R generously calls 'lazy
evaluation'. I'm afraid I don't have a reference at hand, but search the
archives for mention of the promise mechanism.
MW
Thanks,
-Sergio.
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and provide commented, minimal, self-contained, reproducible code.