List Of Tuples (string, Float)with Nan How To Get The Min Value?

I have a list of List of Tuples (string, float) with float('nan'). How can i get the tuple with the smallest number? If I use min I always get the nan. [('GroundBasedMechWT', nan),

Solution 1:

You can use a custom key, that will return a very high value for NaN:

min(list, key=lambda x: float('inf') if math.isnan(x[1]) else x[1])

Solution 2:

You could also try this:

min(filter(lambda t: not math.isnan(t[1]), l), key=itemgetter(1))

where itemgetter refers to operator.itemgetter.

Solution 3:

>>>nan=float('NaN')>>>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
False
>>>nan<1.0
False
>>>min(x)
('CableManualCTL', nan)

I don't think nan is considered smaller than regular floats. Probably min is comparing the strings alphabetically.

(Not a complete answer, but might help)

Solution 4:

nan=float('NaN')
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)]
val=('foo', float('Inf')) #thanks for teaching me thatfor tup in x:
    if tup[1]<val[1]:
        val=tup
print val

Fails on the empty list, but otherwise solves the problem.