R/utils.R

In zkamvar/digroot: Calculate Digital Roots of Integers

sum_string <- function(i) {
	paste(sprintf("%sL", i), collapse = " + ")
}

make_sum_strings <- function(x) {
	xc <- strsplit(as.character(x), "")
	xc <- vapply(xc,
		     FUN = sum_string,
		     FUN.VALUE = character(1)
		    )
	xc
}

eval_sum_strings <- function(x) {
	x <- paste(x, collapse = ", ")
	eval(parse(text = paste0("c(", x, ")")))
}

assert_integer <- function(x) {
	xc <- as.character(x)
	if (any(grepl('[^0-9]', xc))) {
		stop("x does not appear to be an integer", call. = FALSE)
	}
	xc
}