Nsryjdtyk

I need to implement a function that returns the index of the maximum value of a list. I wrote that but it doesn't work. Could someone tell me why?

def maximum_index(lst):

    maximum=0

    index=0

    for i,value in enumerate(lst):

        if value>maximum:

            maximum=value

            index=i

    return index

Your code seemed fine to me. I think the only problem is your indentation and that you only check positive values. The way it is indented everything is outside of the function.

Also I added Chris_Rands suggestion of starting with a check, whether the list is empty. Here you go:

def maximum_index(lst):

    if not lst: 

        return None



    first = True

    maximum=0

    index=0

    for i,value in enumerate(lst):

        if value > maximum or first:

            first = False

            maximum = value

            index = i

    return index

a better way is to just use max directly:

max(enumerate(lst), key=lambda pair: pair[1], default=(None, None))[0]

enumerate yields (idx, value) tuples for the list, the key checks for the max based on only the value, and then [0] grabs the idx from the tuple from enumerate

Use max built-in function to find the maximum value and index method to find its index:

def maximum_index(lst):

  if (not lst):

    return None

  return lst.index(max(lst))

Test it:

print(maximum_index([1, 2, 3, 9, 8, 7, 6]))

print(maximum_index())

Output:

3

None

If you aren't allowed to use max and index as suggested by @Ayxan, you should start the loop assuming that the first element is the max, and then updating accordingly.

def maximum_index(lst):

    if not lst:  # check if list is empty

        return None



    # initialize maximum and index

    index = None

    maximum = lst[0]



    # loop and update

    for i, value in enumerate(lst):

        if value > maximum:

            maximum = value

            index = i



    # return index

    return index





alist = [5, 6, 1, 199, -1, 0, 12]

print(maximum_index(alist))

print(maximum_index())