def fibonacci_sequence():
a,b = 1,1
while True:
yield a
a,b = b, a+b
for i in range(10):
print(fibonacci_sequence().__next__())
I tried using this in Python 3 to print out the fibonacci series. But the program just ends up printing 1 over and over again
You are declaring on each iteration a new generator you need to create one outside of the loop.
def fibonacci_sequence():
a,b = 1,1
while True:
yield a
a,b = b, a+b
generator = fibonacci_sequence()
for i in range(10):
print(generator.__next__())
You could also use next()
generator = fibonacci_sequence()
for i in range(10):
print(next(generator))
As said already, you need to instantiate the generator once only, outside the loop.
Also, avoid calling __next__ directly, use next(generator/iterator) instead.
Having said that, in this simple case just let the for instruction handle the iteration protocol (i.e. call iter, call next and catch the StopIteration exception).
We can also write the loop as:
import itertools as it
def fibonacci_sequence():
a,b = 1,1
while True:
yield a
a,b = b, a+b
for k in it.islice(fibonacci_sequence(),10):
print(k)
You are re-initializing the fibonacci_sequence each time in loop, do it like this:
def fibonacci_sequence():
a,b = 1,1
while True:
yield a
a,b = b, a+b
f = fibonacci_sequence()
for i in range(10):
print(next(f))
fibonnacci_sequence()and then you call__next__()on that new object, so of course, you only ever get the first value. As an aside, the whole point of generators is that you can iterate directly over them (they are iterators). Note also, you shouldn't call dunder methods directly, so if you do need it, usenext(some_iterator)notsome_iterator.__next__()