largest_product_in_a_series.py

# https://projecteuler.net/problem=8
from functools import reduce  # Required for Python 3.*
import operator


# Simple multiplication function.
def prod(iterable: list()) -> int:
    return reduce(operator.mul, iterable)


def largest_n_adjacent_product_in_a_series(series_number: int, n: int) -> int:
    series = [int(x) for x in str(series_number)]
    largest_multiple = float('-inf')
    for i in range(len(series)-n):
        largest_multiple = max(largest_multiple, prod(series[i:i+n]))
    return largest_multiple


large_number = 7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450

print(largest_n_adjacent_product_in_a_series(large_number, 13))