simulate "lazy map" of Clojure in Python, which can just iterate given times with an infinite loop

gistfile1.py

### In Clojure, it's written as "take 5 (nToTicket (iterate inc))"
def inc():
	n = 0
	while True:
		yield n
		n += 1

def lazyMap(f, xs, times=None):
	time = 0
	for x in xs():
		if times and time < times:
			time += 1
			yield f(x)
		else:
			return

### Test
def nToTicket(n):
	return "Ticket %d" % n

for m in lazyMap(nToTicket, inc, 5):
	print m