Available free for the typing are the functions for the default and
the dataframe methods of subset:
> subset.default
function (x, subset, ...)
{
if (!is.logical(subset))
stop("'subset' must be logical")
x[subset & !is.na(subset)]
}
> subset.data.frame
function (x, subset, select, drop = FALSE, ...)
{
if (missing(subset))
r <- TRUE
else {
e <- substitute(subset)
r <- eval(e, x, parent.frame())
if (!is.logical(r))
stop("'subset' must evaluate to logical")
r <- r & !is.na(r)
}
if (missing(select))
vars <- TRUE
else {
nl <- as.list(1:ncol(x))
names(nl) <- names(x)
vars <- eval(substitute(select), nl, parent.frame())
}
x[r, vars, drop = drop]
}
(There is also a matrix method.)
--
David Winsemius
On Dec 17, 2008, at 2:07 PM, GOUACHE David wrote:
Hello R-helpers,
I'm writing a long function in which I manipulate a certain number
of datasets. I want the arguments of said function to allow me to
adapt the way I do this. Among other things, I want my function to
have an argument which I will pass on to subset() somewhere inside
my function. Here is a quick and simplified example with the iris
dataset.
myfunction<-function(table, extraction) {
table2<-subset(table, extraction)
return(table2) }
myfunction(iris, extraction= Species=="setosa")
############## end
What I would like is for this function to return exactly the same
thing as :
subset(iris, Species=="setosa")
Thanks for your help.
Regards,
David Gouache
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______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
