[Rd] Should Position() use match.fun()?

[Kurt Hornik]

>>>>> Kurt Hornik writes:

>>>>> Steve Martin writes:
>> Hello,
>> All of the funprog functions except Position() use match.fun() early
>> in the body of the function. (Filter() seems to rely on lapply() for
>> this, but the effect is the same.) 

> Right. 

>> In most cases this isn't a problem, but I can't see why Position()
>> shouldn't look something like

>> Position2 <- function(f, x, right = FALSE, nomatch = NA_integer_) {
>> f <- match.fun(f) # the only difference from Position()
>> ind <- if (right) rev(seq_along(x)) else seq_along(x)
>> for (i in ind) {
>> if (f(x[[i]])) return(i)
>> }
>> nomatch
>> }

>> This would make it consistent with the other funprog functions, and
>> would mean that Find() and Position() give the same result when
>> expected

> Indeed.  I'll look into adding the match.fun ...

Changed now with c80873.

Best
-k

> Best
> -k

>>> equals3 <- function(x) x == 3
>>> Position("equals3", 1:5)
>> Error in f(x[[i]]) : could not find function "f"
>>> Position2("equals3", 1:5)
>> [1] 3
>>> Find("equals3", 1:5)
>> [1] 3

>> Thanks,
>> Steve

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