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#' Experimental iterator based version of llply.
#'
#' Because iterators do not have known length, \code{liply} starts by
#' allocating an output list of length 50, and then doubles that length
#' whenever it runs out of space. This gives O(n ln n) performance rather
#' than the O(n ^ 2) performance from the naive strategy of growing the list
#' each time.
#'
#' @section Warning:Deprecated, do not use in new code.
#' @seealso \code{\link{plyr-deprecated}}
#' @keywords manip
#' @param .iterator iterator object
#' @param .fun function to apply to each piece
#' @param ... other arguments passed on to \code{.fun}
#' @export
# EXCLUDE COVERAGE START
liply <- function(.iterator, .fun = NULL, ...) {
.Deprecated("llply")
stopifnot(inherits(.iterator, "iter"))
if (is.null(.fun)) return(as.list(.iterator))
iterator <- itertools::ihasNext(.iterator)
if (is.character(.fun)) .fun <- each(.fun)
if (!is.function(.fun)) stop(".fun is not a function.")
result <- vector("list", 50)
i <- 0
while(itertools::hasNext(iterator)) {
piece <- iterators::nextElem(iterator)
res <- .fun(piece, ...)
# Double length of vector when necessary. Gives O(n ln n) performance
# instead of naive O(n^2)
i <- i + 1
if (i > length(result)) {
length(result) <- length(result) * 2
}
if (!is.null(res)) result[[i]] <- res
}
length(result) <- i
result
}
#' Split iterator that returns values, not indices.
#'
#' @section Warning:Deprecated, do not use in new code.
#' @seealso \code{\link{plyr-deprecated}}
#' @keywords internal
#' @export
isplit2 <- function (x, f, drop = FALSE, ...) {
.Deprecated(c("splitter_d", "splitter_a"))
it <- iterators::isplit(seq_len(nrow(x)), f, drop = drop, ...)
nextEl <- function() {
i <- iterators::nextElem(it)
x[i$value, , drop = FALSE]
}
structure(list(nextElem = nextEl), class = c("abstractiter", "iter"))
}
# EXCLUDE COVERAGE END
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