R/CBIND.R

In mrdwab/AMsnippets: Useful function "snippets"

#'cbind \code{data.frames} with different number of rows
#'
#'\code{\link{cbind}} does not work when trying to combine \code{data.frame}s
#'with differing numbers of rows. This function takes a \code{list} of
#'\code{data.frame}s, identifies how many extra rows are required to make
#'\code{cbind} work correctly, and does the combining for you.
#'
#'The \code{\link{CBIND}} function also works with nested lists by first
#'"flattening" them using the \code{\link{LinearizeNestedList}} function by
#'Akhil S Bhel.
#'
#'@param datalist A \code{list} of \code{data.frame}s that you want to combine
#'by columns.
#'@author Ananda Mahto
#'@seealso \code{\link{cbind}}, \code{\link[gdata:cbindX]{cbindX}},
#'\code{\link{LinearizeNestedList}}
#'@examples
#'
#'# Example data
#'df1 <- data.frame(A = 1:5, B = letters[1:5])
#'df2 <- data.frame(C = 1:3, D = letters[1:3])
#'df3 <- data.frame(E = 1:8, F = letters[1:8], G = LETTERS[1:8])
#'
#'CBIND(list(df1, df2, df3))
#'
#'# Nested lists:
#'test1 <- list(list(df1, df2, df3), df1)
#'str(test1)
#'
#'CBIND(test1)
#'\dontshow{rm(df1, df2, df3, test1)}
#'
CBIND <- function(datalist) {
  datalist <- LinearizeNestedList(datalist)
  nrows <- max(sapply(datalist, nrow))
  expandmyrows <- function(mydata, rowsneeded) {
    temp1 = names(mydata)
    rowsneeded = rowsneeded - nrow(mydata)
    temp2 = setNames(data.frame(
      matrix(rep(NA, length(temp1) * rowsneeded),
             ncol = length(temp1))), temp1)
    rbind(mydata, temp2)
  }
  do.call(cbind, lapply(datalist, expandmyrows, rowsneeded = nrows))
}