R/l2df.R

In brry/berryFunctions: Function Collection Related to Plotting and Hydrology

#' List to data.frame
#' 
#' Convert list with vectors of unequal length to dataframe, pad with NAs
#' 
#' @return data.frame
#' @author Berry Boessenkool, \email{berry-b@@gmx.de}, Jan 2014
#' @seealso \code{\link{l2array}}, \code{\link{sapply}}, \code{\link{sortDF}}.
#'          If you have a LARGE list each with the same number of values,
#'          use the (much!) faster: \code{\link{simplify2array}} or \code{plyr::quickdf}.
#' @references
#'   \url{https://stackoverflow.com/questions/5531471/combining-unequal-columns-in-r}\cr
#'   \url{https://stackoverflow.com/questions/15753091/convert-mixed-length-named-list-to-data-frame}\cr
#'   \url{https://stackoverflow.com/questions/5942760/most-efficient-list-to-data-frame-method}\cr
#'   \url{https://stackoverflow.com/questions/8799990/converting-given-list-into-dataframe}\cr
#'   \url{https://stackoverflow.com/questions/4227223/r-list-to-data-frame}
#' @keywords list manip
#' @export
#' @examples
#' 
#' eglist <- list(AA=c(6,9,2,6), BB=1:8, CC=c(-3,2) )
#' eglist
#' l2df(eglist)  # names are even kept
#' l2df(eglist, byrow=FALSE)
#' class(  l2df(eglist, byrow=FALSE)  ) # data.frame (since 2016-05-24)
#' 
#' eglist <- list(AA=c(6,9,2,6), BB="no", CC=c(-3,2) )
#' eglist
#' str(l2df(eglist))  # now everything is a character
#' 
#' eg2 <- list(AA=c(6,9,2,6), BB=matrix(1:8, ncol=2), CC=c(-3,2) )
#' eg2
#' l2df(eg2, FALSE)
#' # so a matrix is internally converted to a vector and then used regularly
#' 
#' 
#' # Naming ----
#' 
#' eg3 <- list(EE=c(AA=3.4),        FF=c(AA=3.5),        GG=c(AA=3.6))
#' eg4 <- list(EE=c(AA=3.4,BB=2.4), FF=c(AA=3.5,BB=2.5), GG=c(AA=3.6,BB=2.6))
#' l2df(eg3)
#' l2df(eg4)
#' l2df(eg3, byrow=FALSE)
#' l2df(eg4, byrow=FALSE)
#' 
#' eg3 <- list(c(AA=3.4),        c(AA=3.5),        c(AA=3.6))
#' eg4 <- list(c(AA=3.4,BB=2.4), c(AA=3.5,BB=2.5), c(AA=3.6,BB=2.6))
#' l2df(eg3)
#' l2df(eg4)
#' l2df(eg3, byrow=FALSE)
#' l2df(eg4, byrow=FALSE)
#' 
#' eg3 <- list(EE=c(3.4),     FF=c(3.5),     GG=c(3.6))
#' eg4 <- list(EE=c(3.4,2.4), FF=c(3.5,2.5), GG=c(3.6,2.6))
#' l2df(eg3)
#' l2df(eg4)
#' l2df(eg3, byrow=FALSE)
#' l2df(eg4, byrow=FALSE)
#' 
#' eg3 <- list(EE=c(3.4),     c(3.5),     c(3.6))
#' eg4 <- list(EE=c(3.4,2.4), c(3.5,2.5), c(3.6,2.6))
#' l2df(eg3)
#' l2df(eg4)
#' l2df(eg3, byrow=FALSE)
#' l2df(eg4, byrow=FALSE)
#' 
#' 
#' # Lists with dfs ----
#' 
#' eg5 <- list(AA=c(6,9,2,6), BB=data.frame(CC=1:8, DD=4:-3), EE=c(-3,2) )
#' eg5
#' is.error( l2df(eg5), tell=TRUE )# it is not possible to do this with a data.frame
#' 
#' # If you have a list with only data.frames, you could use the following:
#' eg6 <- list(AA=data.frame(BB=1:8, CC=4:-3), DD=data.frame(EE=23:24, FF=c(-3,2)))
#' eg6
#' do.call(cbind, eg6) # but this recycles the values of shorter tables!
#' colnames(eg6$DD) <- colnames(eg6$AA)
#' do.call(rbind, eg6)
#' # check some of the links above for more solutions...
#' 
#' @param list List with vectors of irregular length.
#' @param byrow Transposed output? DEFAULT: TRUE
# @param makenames Logical: (try to) create names correctly?
#                  Set to FALSE if list elements are only partially named.
#                  DEFAULT: TRUE
#' 
l2df <- function(
list,
byrow=TRUE)
{
cls <- unlist(sapply(list, class))
if("data.frame" %in% cls) stop(paste("l2df does not work for lists with data.frames.",
                               "Use r/c-bind instead: do.call(rbind, yourlist)"))
maxlen <- max(sapply(list,length))
df <- sapply(list, "[", 1:maxlen) # apply the indexing function to each element
###cn <- colnames(df)
df <- as.data.frame(df, stringsAsFactors=FALSE)
###if(byrow & checknames & maxlen>1) colnames(df) <- cn
if(maxlen==1)
  {
  n1 <- names(list[[1]])
  if(is.null(n1)) n1 <- "V1"
  colnames(df) <- n1
  n2 <- names(list)
  if(!any(duplicated(n2))) rownames(df) <- n2
  }
if(maxlen==1) byrow <- !byrow
if(byrow) df <- as.data.frame(t(df), stringsAsFactors=FALSE)
df
}