How to obtain the last index of a list?

Question

Suppose I've the following list:

list1 = [1, 2, 33, 51]                     ^                     | indices  0  1   2   3 

How do I obtain the last index, which in this case would be 3, of that list?

Answer 1

len(list1)-1 is definitely the way to go, but if you absolutely need a list that has a function that returns the last index, you could create a class that inherits from list.

class MyList(list):     def last_index(self):         return len(self)-1   >>> l=MyList([1, 2, 33, 51]) >>> l.last_index() 3 

Answer 2

The best and fast way to obtain the content of the last index of a list is using -1 for number of index , for example:

my_list = [0, 1, 'test', 2, 'hi'] print(my_list[-1]) 

Output is: 'hi'.

Index -1 shows you the last index or first index of the end.

But if you want to get only the last index, you can obtain it with this function:

def last_index(input_list:list) -> int:     return len(input_list) - 1 

In this case, the input is the list, and the output will be an integer which is the last index number.