R/uniqueID.R

In mhweber/spsurvey: Spatial Survey Design and Analysis

################################################################################
# Function: uniqueID
# Programmer: Tom Kincaid
# Date: February 23, 2004
# Last Revised: June 27, 2005
#
#' Internal Function: Create Unique IDs for a Survey Design
#'
#' This function creates unique site IDs by appending a unique number to each
#' occurrence of a site ID.  It is intended for survey designs that have repeat
#' visits to sites.
#'
#' @param siteID  Vector of site IDs.
#'
#' @return Vector of unique site IDs.
#'
#' @author Tom Kincaid \email{Kincaid.Tom@epa.gov}
#'
#' @export
################################################################################

uniqueID <- function(siteID) {

# If siteID is a factor, convert the input vector to character data

   factor.ind <- FALSE
   if(is.factor(siteID)) {
      siteID <- as.character(siteID)
      factor.ind <- TRUE
   }

# Assign new site IDs

   for(id in unique(siteID)) {
      temp <- siteID == id
      if(sum(temp) > 1)
         siteID[temp] <- paste(siteID[temp], 1:sum(temp), sep=".")
   }

# If siteID is a factor, convert the result to a factor

   if(factor.ind)
      siteID <- as.factor(siteID)

# Return the vector of site IDs

   siteID
}