R/helper.R

In memofunc: Function Memoization

##
# Helper function to get the first n of a list
#
first.n <- function (x, n=1) x[c(1:n)]
`%<n>%` <- function (x, n=1) first.n(x,n)

##
# Helper to get the rest of a given list
#
rest <- function (x) if (length(x) <= 1) list() else x[2:length(x)]

##
# Helper function to pad out a list to size n with a specified value defaulting to NA
#
pad <- function (x, n, by=NA) lapply(1:n, function (index) if (index > length(x)) x[[index]] <- by else x[[index]])

##
# Helper function to order arguments by name
#
orderby.name <- function (args) if (length(args) != 0 && !is.null(names(args))) args[order(names(args))] else args

##
# Helper function to remove an item from a list
#
removeby.name <- function (x, name) if (name %in% names(x)) x[sapply(names(x), `!=`, y = name)] else x