How to select starting letter in a list of letters

Question

I have a list of letters. As of right now, I am able to allocate my starting point based on the index point (IE: 0 = 'A', 1 = 'B', 2 = 'C', etc).

def moving_letters():
    letters = ['A','B','C','D','E','F','G']
    *user = int(input('Enter starting index #: '))* 
    print(letters[user], letters[(user + 5) % len(letters)], letters[(user + 7) % len(letters)])


print(moving_letters())

How would I be able to select a specific letter in my list as a starting point?

Also, how would I be able to move my starting point as showed in?:

print(letters[user], letters[(user + 5) % len(letters)], 
    letters[(user + 7) % len(letters)])

It is not clear what you are trying to do, but your function does not return anything. — DYZ, Jan 12 '22 at 03:31
and what exactly is the problem? also note that `(x+n)%n` is the same as `x%n` that in your particular example that is n=7 — Copperfield, Jan 12 '22 at 03:51
perhaps the issue is that you don't show the user what are the options? if so, well just show the user what are the options, beside that I don't see anything particularly wrong with that sample code (ignoring the `*` of course) tho is unclear what the goal of the function is — Copperfield, Jan 12 '22 at 04:01
If the function does its own printing, you shouldn't call `print()` again when calling it. You're just going to print an extra `None`. — Barmar, Jan 12 '22 at 04:17
If you want to let the user select the letter instead of index, you can use `letters.index(user)` to get its index. — Barmar, Jan 12 '22 at 04:18
@Barmar, yes I want the user to select the letter and then move down the list based on the selected letter. — poptart20, Jan 12 '22 at 04:55
So what problem are you having? Doesn't the `index()` method work for that? — Barmar, Jan 12 '22 at 16:50

score 1 · Accepted Answer · answered Jan 12 '22 at 08:33

You can select a slice of a list with : in the index, where you can specify start and end, if either is left empty you select everything. After you have a slice of a list selected, you can use join to make a line to print. Keep in mind the items you are joining have to be strings.

def moving_letters():
    letters = ['A','B','C','D','E','F','G']
    user = int(input('Enter starting index #: '))
    s = " ".join(letters[user:])
    print(s)

moving_letters()

Slice notation: Understanding slice notation

String join: What exactly does the .join() method do?

How to select starting letter in a list of letters

1 Answers1