List index beginner

Python
1

Hello!Please,help to understand,what does this part of code do lst[end+1:],all the other is Ok)Thank you!Why do we have output 4,23,42 not 4,42,1?

def remove_middle(lst, start, end):
  return lst[:start] + lst[end+1:]

#Uncomment the line below when your function is done
print(remove_middle([4, 8, 15, 16, 23, 42], 1, 3))
2

I suggest you review slice syntax

there is no a 1 in the input list, how could it appear in the list on its own?

3

It is important to remember that lists are zero indexed, meaning that the first element is at position 0 and the second at position 1 etc.

Slicing is not inclusive, which means it will start with the first index and go up until, but not include, the last index.

lst[:3]

The above would start at the beginning (lists being zero indexed) and go up to the element at position 3 (which is 16 in your example) but not include it:

Result:

[4, 8, 15]

You are doing this twice and then concatenating (joining) this lists.

Taking the above into consideration, all the +1 does in your code is make the function inclusive, so that it goes up to and includes the element at the index you have provided.

1 Like