def extractEneDiff(lineList):
    """
    This function is used by loadPd_q  to extract the energy from a line of the clean data set.

    :param lineList: line with geometries in clean format, partial charges and energies
    :return: energy difference (float)
    """
    enePart = lineList[-2:]
    eneDiff = float(enePart[1]) - float(enePart[0])
    return eneDiff