problem00040.py

#!/usr/bin/env python

# Champernowne's constant

# Problem 40
# An irrational decimal fraction is created by concatenating the positive integers:

#     0.123456789101112131415161718192021...

# It can be seen that the 12th digit of the fractional part is 1.

# If dn represents the nth digit of the fractional part, find the value of the following expression.

#     d1 × d10 × d100 × d1000 × d10000 × d100000 × d1000000

import math
from functools import reduce

s = ''.join(map(str, range(1, 1000001)))
print(reduce(lambda x, y: x * y, map(int, map(lambda i: s[i - 1], map(lambda i: int(math.pow(10, i)), range(7))))))