import time, operator

try:
	xrange
except NameError:
	xrange= range

class A(object):
	def __init__(self):
		self.id= id(self)

def main():
	alist= [A() for _ in xrange(1000000)]

	t0= time.clock()
	data= [obj.id for obj in alist]
	t= time.clock() - t0

	print("list comp", t, len(data))

	t0= time.clock()
	data= list(map(operator.attrgetter('id'), alist))
	t= time.clock() - t0
	
	print("map attrgetter", t, len(data))

	t0= time.clock()
	data= list(map(lambda x: x.id, alist))
	t= time.clock() - t0

	print("map lambda", t, len(data))

main()