Convert list or numpy array of single element to float in python

Question

I have a function which can accept either a list or a numpy array.

In either case, the list/array has a single element (always). I just need to return a float.

Answer 1

I would simply use,

np.asarray(input, dtype=np.float)[0]

• If input is an ndarray of the right dtype, there is no overhead, since np.asarray does nothing in this case.
• if input is a list, np.asarray makes sure the output is of the right type.