R/lcPostfix.R

In tsieger/tsiMisc: Miscelaneous utility functions, mostly related to exploratory statistical analysis

lcPostfix<-structure(
function # Longest common postfix.
##description<<
## \code{\link{lcPostfix}} returns the longest common postfix of
## a vector of strings.
##
##details<<
##
##seealso<< \code{\link{lcPrefix}},\code{\link{rmLcPostfix}}
##
(x, ##<< a vector of character strings
ignore.case = FALSE ##<<
) {
  x <- as.character(x)
  if (length(x)<2) return(x)
  if (ignore.case) x <- toupper(x)
  nc <- nchar(x, type = "char")
  if (min(nc)>0) {
    for (i in rseq(1,min(nc),1)) {
      ss <- substr(x, nc-i+1, nc)
      if (any(ss != ss[1])) {
        return(substr(x[1], nc-i+2, nc))
      }
    }
    return(substr(x[1], nc-min(nc)+1, nc))
  }
  return('')
  ### A character string vector having the longest common postfix removed.
},ex=function() {
  lcPostfix(c('abab','cdab'))
})