Sierpinski triangles

gistfile1.txt

"""
Usage: test.py [l|c|r] <n>
Print a Sierpinski's Gasket of iteration n, left, center, or right-aligned (accordingly)
"""
import string, sys

def sierpinski(n, c):
  gasket = [c]
  for i in range(1, n+1):
    gasket += ['{0}{0:>{1}}'.format(j, 2**i) for j in gasket]
  return gasket

if __name__ == '__main__':
  just, char = {'l': (string.ljust,  'L'),
                'c': (string.center, 'A'),
                'r': (string.rjust,  'J')
               }[sys.argv[1]]

  n = int(sys.argv[2])
  gasket = sierpinski(n, char)
  print '\n'.join(just(r, 2**(n+1)) for r in gasket)