# File lib/core/facets/string/nchar.rb, line 21
  def nchar(n, replacement=nil)
    if replacement
      s = self.dup
      n > 0 ? (s[0...n] = replacement) : (s[n..-1] = replacement)
      s
    else
      n > 0 ? self[0...n] : self[n..-1]
    end
  end