Code to output the first repeated character in given string?

Question

I\'m trying to find the first repeated character in my string and output that character using python. When checking my code, I can see I\'m not index the last character of my co

Answer 1

If complexity is not an issue then this will work fine.

letters = 'acbdc'
found = False
for i in range(0, len(letters)-1):
    for j in range(i+1, len(letters)):
        if (letters[i] == letters[j]):
            print (letters[j])
            found = True
            break
    if (found):
        break

Answer 2

Here's a solution with sets, it should be slightly faster than using dicts.

letters = 'acbdc'
seen = set()

for letter in letters:
    if letter in seen:
        print(letter)
        break
    else:
        seen.add(letter)

Answer 3

Nice one-liner generator:

l = 'acbdc'
next(e for e in l if l.count(e)>1)

Or following the rules in the comments to fit the "abba" case:

l = 'acbdc'
next(e for c,e in enumerate(l) if l[:c+1].count(e)>1)