Is there an easy way to get the number of repeating character in a word?

Question

I'm trying to get how many any character repeats in a word. The repetitions must be sequential.

For example, the method with input "loooooveee" should return 6 (4 times 'o', 2 times 'e').

I'm trying to implement string level functions and I can do it this way but, is there an easy way to do this? Regex, or some other sort of things?

Answer 1

Original question: order of repetition does not matter

You can subtract the number of unique letters by the number of total letters. set applied to a string will return a unique collection of letters.

x = "loooooveee"
res = len(x) - len(set(x))  # 6

Or you can use collections.Counter, subtract 1 from each value, then sum:

from collections import Counter

c = Counter("loooooveee")

res = sum(i-1 for i in c.values())  # 6

New question: repetitions must be sequential

You can use itertools.groupby to group sequential identical characters:

from itertools import groupby

g = groupby("aooooaooaoo")
res = sum(sum(1 for _ in j) - 1 for i, j in g)  # 5

To avoid the nested sum calls, you can use itertools.islice:

from itertools import groupby, islice

g = groupby("aooooaooaoo")
res = sum(1 for _, j in g for _ in islice(j, 1, None))  # 5