def my_max(*a): n = len(a) max_v = a for i in range (1,n): if a[i] > max_v: max_v = a[i] return max_v def my_min(*a): n = len(a) min_v = a for i in range (1,n): if a[i] < min_v: min_v = a[i] return min_v test = [7, 4, 2, 6, 8] assert max(test) == my_max(test) and min(test) == my_min(test) assert max(7, 4, 2, 5) == my_max(7, 4, 2, 5) and min(7, 4, 2, 5) == my_min(7, 4, 2, 5) print("pass")
I am trying to write the max() function of python in codes.
If I add the asterisk in front of the input, it won’t pass the first assertion.
If I don’t it wouldn’t pass the second assertion.
What should I write in input for it to pass both assertions like it does in max() function of python?
Short answer: Use a star to collect the arguments in a tuple and then add a special case for a tuple of length one to handle a single iterable argument.
Source material: The C code that handles the logic can be found at: https://github.com/python/cpython/blob/da20d7401de97b425897d3069f71f77b039eb16f/Python/bltinmodule.c#L1708
Simplified pure python code: If you ignore the default and key keyword arguments, what’s left simplifies to:
def mymax(*args): if len(args) == 0: raise TypeError('max expected at least 1 argument, got 0') if len(args) == 1: args = tuple(args) largest = args for x in args[1:]: if x > largest: largest = x return largest
There are other nuances, but this should get you started.
Documentation: The special handling for the length one case versus other cases is documented here:
Return the largest item in an iterable or the largest of two or more
If one positional argument is provided, it should be an iterable. The
largest item in the iterable is returned. If two or more positional
arguments are provided, the largest of the positional arguments is