python - 开始Python斐波那契生成器

Question

我正在尝试制作一个在给定数量处停止的斐波那契数生成器，但它通常会超过该数量。我做错了什么？

#Fibonacci number generator
a=0
b=1
print("Fibonacci number generator.")
stopNumber=input("How high do you want to go? If you want to go forever, put n.")
print(1)
while stopNumber=="n":
        a=a+b
        b=b+a
        print(a)
        print(b)
else:
    while int(stopNumber) > a or int(stopNumber) > b:
        a=a+b
        b=b+a
        print(a)
        print(b)

Answer 1

同样的，工作并使用一些更聪明的技术:

# returns generator
def fib(stop):
    prev, current = 0, 1
    while current < stop:  # a little hack here - python is ok comparing ints to floats
        yield current
        # multiple assginment - operands on the left are "frozen" just before theis instruction
        prev, current = current, prev + current 

# note inf - float('inf') results in "positive infinity" which is an appropriate math concept for "forever"
stop = float(input("How high do you want to go? If you want to go forever, put inf."))

for f in fib(stop):
    print (f)

注意:请不要尝试执行 list(fib(float('inf'))) :)