On 28/09/2009, at 4:30 PM, David Winsemius wrote:
On Sep 27, 2009, at 11:07 PM, Rolf Turner wrote:
On 28/09/2009, at 3:36 PM, trumpetsaz wrote:
I am trying to write a function that will have an input of a vector
of
functions. Here is a simplistic example.
sumstats <- c(mean,sd)
sumstats[1]
#Gives this error
#> sumstats[1]
#[[1]]
#function (x, ...)
#UseMethod("mean")
#<environment: namespace:base>
I thought about restricting the input to character variables such
as the
following
sumstats2 <- c("mean","sd")
Is there a way to change "mean" to the function mean?
You *can't* have a vector of functions, as far I know. The entries
of a vector must be (numeric, character, or logical) scalars.
You *can* have a *list* of functions; this might be the way you
want to go.
To ``change "mean" to the function mean'' --- set ?get.
That is prezactly what he created:
umstats <- c(mean,sd)
str(umstats)
List of 2
$ :function (x, ...)
$ :function (x, na.rm = FALSE)
And what's more "it works" if it is accessed with "[[":
umstats[[1]](c(1,2,3,4,5))
[1] 3
Never ceases to amaze me how R can get it right in settings and
with syntaxes that you would think can't ***possibly*** work!
cheers,
Rolf Turner
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