def getIntervalStr( rg, label ):
  """ Converts and stores range along string as string

  Parameters:
    * rg (list, array, tuple): array object with three elements [start, stop, step]
    * label (str): label to be concatenated with range info

  Returns:
    * str: concatenated label and range info

  """

  if len(rg) < 3:
    return
  str = label + " range: "+ repr(rg[0]) + "-" + repr(rg[1])
  str = str + " (step " + repr(rg[2]) + ")"
  return str