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library(iterators)
# Returns a filtering iterator
ifilter <- function(it, FUN, ...) {
it <- iter(it)
nextEl <- function() {
repeat {
x <- nextElem(it)
if (FUN(x, ...))
break
}
x
}
obj <- list(nextElem=nextEl)
class(obj) <- c('ifilter', 'abstractiter', 'iter')
obj
}
# Simple example use
it <- irnorm(1, count=10)
is.positive <- function(x) x > 0
print(as.list(ifilter(it, is.positive)))
# Example using a function with an additional argument
it <- irnorm(1, count=10)
greater.than <- function(x, y) x > y
print(as.list(ifilter(it, greater.than, 1.0)))
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