`interleave` from "gdata" with a `list` as an input.

Interleave.R

Interleave <- function(myList, append.source = TRUE, sep = ": ", drop = FALSE) {
  sources <- myList
  sources[sapply(sources, is.null)] <- NULL
  sources <- lapply(sources, function(x) if (is.matrix(x) || 
                                               is.data.frame(x)) 
    x
                    else t(x))
  nrows <- sapply(sources, nrow)
  mrows <- max(nrows)
  if (any(nrows != mrows & nrows != 1)) 
    stop("Arguments have differening numbers of rows.")
  sources <- lapply(sources, function(x) if (nrow(x) == 1) 
    x[rep(1, mrows), , drop = drop]
                    else x)
  tmp <- do.call("rbind", sources)
  nsources <- length(sources)
  indexes <- outer((0:(nsources - 1)) * mrows, 1:mrows, "+")
  retval <- tmp[indexes, , drop = drop]
  if (append.source && !is.null(names(sources))) 
    if (!is.null(row.names(tmp))) 
      row.names(retval) <- paste(format(row.names(retval)), 
                                 format(names(sources)), sep = sep)
  else row.names(retval) <- rep(names(sources), mrows)
  retval
}