To find the index of the maximum value in the list, use list.index + python code example

Example 1: python index of max value in list

# any list
a = [1, 7, 3, 12, 5]

# index of minimum element
# if more than 1 minimum, 
# first index is returned
min_index = a.index(min(a))

# index of maximum element
max_index = a.index(max(a))

Example 2: max of list with index

a.index(max(a))