Time string formatting

Time.rb

class Time
  def format_compact(precision = :second, inc_utc = true)
    prec = [:year, :month, :day, :hour, :minute, :second].index precision
    fmt_a = ["%Y","%m","%d","_%H","%M","%S"][0..prec]
    fmt = fmt_a.join('')
    self.strftime("#{fmt}#{'%Z' if inc_utc}")
  end
  def format_datestamp(inc_utc = true)
    self.strftime("%Y%m%d#{'%Z' if inc_utc}")
  end
end