import random def randomperm(n): x = range(n) for i in xrange(n): r = random.randint(i,n-1) (x[i],x[r]) = (x[r], x[i]) return x if __name__ == "__main__": import sys if len(sys.argv) < 2: print "usage: python randomperm n" n = int(sys.argv[1]) print randomperm(n)