[R] which.pmin?
Seung Jun
jun at cc.gatech.edu
Fri Jan 21 23:26:41 CET 2005
I have two vectors (k.floor and k.ceiling) of integers of the same
length, and a function (fpr).
b <- 10:40
k.floor <- floor(log(2) * b)
k.ceiling <- ceiling(log(2) * b)
fpr.floor <- fpr(b, k.floor)
fpr.ceiling <- fpr(b, k.ceiling)
If R had a element-wise ternary function, I'd like to do something like
this:
(fpr.floor < fpr.ceiling) ? k.floor : k.ceiling
That is, I'd like to go through the two vectors in parallel, picking
the one that returns the lower value of fpr. Failing to find such a
function, I wrote the following two lines:
ind <- sapply(data.frame(rbind(fpr.floor,fpr.ceiling)), which.min)
opt.k <- cbind(k.floor,k.ceiling)[1:length(ind)+length(ind)*(ind-1)]
opt.k is the vector I want, but I guess I abuse some functions here.
I'd like to ask the experts, What is the proper R-way to do this?
The API should be like "which.pmin(FUN, X, Y, ...)" that returns a
vector of the same length as X (and Y), provided that X, Y, ... have
the same length. Please fill the function body.
Seung
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