Code Golf Diamond

diamond.py

#!/usr/bin/env python3

output = ["%s%s" % (" "*(9-i), "".join(str(num) for num in list(range(1, i+1)) + list(range(1, i+1))[-2::-1])) for i in range(1, 10)]
print("\n".join(output + output[-2::-1]))

output.txt

cmoultrie@Sauron ~/Desktop> ./diamond.py
        1
       121
      12321
     1234321
    123454321
   12345654321
  1234567654321
 123456787654321
12345678987654321
 123456787654321
  1234567654321
   12345654321
    123454321
     1234321
      12321
       121
        1