R/capitalize.R

In HenrikBengtsson/R.utils: Various Programming Utilities

#########################################################################/**
# @RdocDefault capitalize
# @alias decapitalize
# @alias decapitalize.default
#
# @title "Capitalizes/decapitalizes each character string in a vector"
#
# \description{
#  Capitalizes/decapitalized (making the first letter upper/lower case) of
#  each character string in a vector.
# }
#
# \usage{
#   @usage capitalize,default
#   @usage decapitalize,default
# }
#
# \arguments{
#   \item{str}{A @vector of @character strings to be capitalized.}
#   \item{...}{Not used.}
# }
#
# \value{
#   Returns a @vector of @character strings of the same length as the input
#   vector.
# }
#
# @author
#
# @examples "../incl/capitalize.Rex"
#
# \seealso{
#   @see "R.utils::toCamelCase".
# }
#
# @keyword "programming"
#*/#########################################################################
setMethodS3("capitalize", "default", function(str, ...) {
  # Nothing to do?
  n <- length(str)
  if (n == 0L) {
    return(str)
  }

  # Missing values?
  nas <- is.na(str)
  idxs <- which(nas)
  # All missing values? => nothing to do.
  if (length(idxs) == n) {
    return(str)
  }

  # Allocate result
  res <- character(length=n)

  # Preserve missing values
  if (length(idxs) > 0L) {
    res[idxs] <- NA_character_
  }

  # Capitilize
  idxs <- which(!nas)
  if (length(idxs) > 0L) {
    t <- str[idxs]
    first <- substring(t, first=1L, last=1L)
    tail  <- substring(t, first=2L)
    first <- toupper(first)
    res[idxs] <- paste(first, tail, sep="")
  }

  res
})

setMethodS3("decapitalize", "default", function(str, ...) {
  # Nothing to do?
  n <- length(str)
  if (n == 0L) {
    return(str)
  }

  # Missing values?
  nas <- is.na(str)
  idxs <- which(nas)
  # All missing values? => nothing to do.
  if (length(idxs) == n) {
    return(str)
  }

  # Allocate result
  res <- character(length=n)

  # Preserve missing values
  if (length(idxs) > 0L) {
    res[idxs] <- NA_character_
  }


  # Decapitilize
  idxs <- which(!nas)
  if (length(idxs) > 0L) {
    t <- str[idxs]
    first <- substring(t, first=1L, last=1L)
    tail  <- substring(t, first=2L)
    first <- tolower(first)
    res[idxs] <- paste(first, tail, sep="")
  }

  res
})