R/listProduct.R

In SoilR: Models of Soil Organic Matter Decomposition

tupelize <- function(l){
  lapply(l,list)}
listProduct_append_2D <- function(lol,l){
  res <- unlist(
      recursive=FALSE,
      lapply(
        lol,
        function(tup){
          lapply(l,function(el){append(tup,list(el))})
        }
	    )
  )
  return(res)
}
listProduct_append <- function(lolol){
  lol <- lolol[[1]]
  n <- length(lolol)
  if(n==1){
    res <- lol
  }
  if (n>=2){
    res <- listProduct_append_2D(lol,lolol[[2]])
    if (n> 2){
      new_lolol <- append(list(res),lolol[3:n])
      res <- listProduct_append(new_lolol)
    }
  }
  return(res)
}






#' tensor product of lists
#' 
#' Creates a list of all combinations of the elements of the inputlists (like a
#' "tensor product list " The list elements can be of any class. The function
#' is used in examples and tests to produce all possible combinations of
#' arguments to a function. look at the tests for example usage
#' 
#' 
#' @param ... lists
#' @return a list of lists each containing one combinations of the elements of
#' the input lists
#' @examples
#' listProduct(list('a','b'),list(1,2))
listProduct<- function
(... 
 ){
  l <- list(...)
  if(!all(as.logical(lapply(l,function(sl){inherits(sl,'list')})))){
    stop('The parmeters of the listProduct have to be lists')
  }
  l[[1]] <- tupelize(l[[1]])
  return(listProduct_append(l))
}