R/expand.dft.R

In ca: Simple, Multiple and Joint Correspondence Analysis

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# expand.dft(): Expand data frames/tables 
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# Author: Marc Schwarz
# Ref: http://tolstoy.newcastle.edu.au/R/e6/help/09/01/1873.html
# This version copied from the vcdExtra package, Michael Friendly
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expand.dft <- function(x, var.names = NULL, freq = "Freq", ...){
  #  allow: a table object, or a data frame in frequency form
  if(inherits(x, "table")){
    x <- as.data.frame.table(x, responseName = freq)
    }
  freq.col <- which(colnames(x) == freq)
  if (length(freq.col) == 0){
    stop(paste(sQuote("freq"), "not found in column names"))
    }
  DF <- sapply(1:nrow(x),
               function(i) x[rep(i, each = x[i, freq.col]), ],
               simplify = FALSE)
  DF <- do.call("rbind", DF)[, -freq.col]
  for (i in 1:ncol(DF)){
    DF[[i]] <- type.convert(as.character(DF[[i]]), ...)
    }
  rownames(DF) <- NULL
  if (!is.null(var.names)){
    if (length(var.names) < dim(DF)[2]){
      stop(paste("Too few", sQuote("var.names"), "given."))
      } else if (length(var.names) > dim(DF)[2]){
      stop(paste("Too many", sQuote("var.names"), "given."))
      } else {
      names(DF) <- var.names
      }
    }
  return(DF)
  }
# make this a synonym
expand.table <- expand.dft
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