x = [('GroundBasedMechWT', nan), ('GroundBasedCTL', nan), (
    'GroundBasedManualWT', nan), ('GroundBasedManualLog', nan), (
    'CableManualWTLog', 60.77), ('CableManualWT', 58.52), ('CableManualLog',
    68.17), ('CableManualCTL', nan), ('HelicopterManualWT', 96.82), (
    'HelicopterManualCTL', nan)]
nan < 1
List of Tuples (string, float)with NaN How to get the min value?