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Python Python Collections (2016, retired 2019) Slices Slice Functions

Posted by Andrew McLane
Andrew McLane
3,385 Points

how to format function to allow for strings.

I got the code to work for lists of numbers, but I can't figure out how to allow for lists that include strings, such as a list of letters.

I need to be able to determine if the last index of a list is even or odd, but I can only think of a way to do so if the list is of numbers.

slices.py 
def first_4(iterable):
    return iterable[0:4]

def first_and_last_4(iterable):
    return iterable[0:4] + iterable[-4:]

def odds(iterable):
    return iterable[1::2]

def reverse_evens(iterable):
    if iterable[-1] % 2 == 0:
        return iterable[::-2]
    else:
        return iterable[:-1:-2]

2 Answers

Afloarei Andrei
Afloarei Andrei
5,163 Points
Afloarei Andrei
Afloarei Andrei
5,163 Points

Try to do it like this: iterable[][*]

*select only the even numbers **invert the numbers

Afloarei Andrei
Afloarei Andrei
5,163 Points
Afloarei Andrei
Afloarei Andrei
5,163 Points

iterable[even numbers][invert list]

Andrew McLane
Andrew McLane
3,385 Points
Andrew McLane
Andrew McLane
3,385 Points

Thanks, I'd like to solve the problem using methods I've learned up to this point, so that I fully understand how they work. I'm not even sure how to input those symbols.

Afloarei Andrei
Afloarei Andrei
5,163 Points
Afloarei Andrei
Afloarei Andrei
5,163 Points

You used those symbols in the challenge: if you want to print the even numbers you do something like in you'r odd function but slightly different. ex: iterable[1::2] is printing the item from the 1 index and it jumps the next and prints the item from index 3. with that in mind make the function to print the even numbers. and the invert list is [::-1] from the videos. Finally put those 2 together and you get something like in my commet.

iterable[even numbers][invert list]