cfax

from decimal import Decimal
 
def is_armstrong_number(number):
    digits = Decimal(number).as_tuple.digits()
    exp = len(digits)
    return sum(d**exp for d in digits) == number
 
def sum_all_armstrong_numbers(start, end):
    start_, end_ = sorted([start, end])
    return sum(number for number in range(start_, end_+1)

cfax

digits :: (Integral n) => n -> [n]
digits = reverse . go
    where go n
            | n < 10 = [n]
            | otherwise = r : digits q
                where (q, r) = n `quotRem` 10

numberLength :: Int -> Int
numberLength = length . digits