code: def mapLabelRefs(dataDict):
    
    labelRefs = [label for label in set(
      itertools.chain.from_iterable([x[1] for x in dataDict.values()]))]
  
    for recordNumber, data in dataDict.iteritems():
      dataDict[recordNumber] = (data[0], numpy.array(
        [labelRefs.index(label) for label in data[1]]), data[2])
  
    return labelRefs, dataDict
docs: Replace the label strings in dataDict with corresponding ints.
  
    @return (tuple)   (ordered list of category names, dataDict with names
                      replaced by array of category indices)