permute_column.r

permute_column.r

# permutes a column in a data.frame, sets seed optionally
permute <- function (dataframe, columnToPermute="column", seed=NULL) {
	if (!is.null(seed)) set.seed(seed)
	colindex <- which(names(dataframe)==columnToPermute)
	permutedcol <- dataframe[ ,colindex][sample(1:nrow(dataframe))]
	dataframe[colindex] <- permutedcol
	return(dataframe)
}