>>> def make_counter(x):
	print('entering make_counter')
	while True:
		yield x
		print('incrementing x')
		x = x + 1

		
>>> counter = make_counter(2)
>>> counter

>>> next(counter)
entering make_counter
2
>>> next(counter)
incrementing x
3
>>> next(counter)
incrementing x
4
>>> next(counter)
incrementing x
5
>>> def fib(max):
	a,b = 0,1
	while a < max: yield a a,b = b, a + b >>> for n in fib(1000):
	print(n,end = ' ')

	
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 
>>> list(fib(1000))
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987]
>>> 

Python Generator の話