A safe max() function for empty lists

Question

Evaluating,

max_val = max(a)

will cause the error,

ValueError: max() arg is an empty sequence

Is there a bett

Answer 1

In Python 3.4+, you can use default keyword argument:

>>> max([], default=99)
99

In lower version, you can use or:

>>> max([] or [99])
99

NOTE: The second approach does not work for all iterables. especially for iterator that yield nothing but considered truth value.

>>> max(iter([]) or 0)
Traceback (most recent call last):
  File "", line 1, in 
ValueError: max() arg is an empty sequence