斐波那契數列(fib) 4種方法實現 171201

• 大綱

• 循環 while

• 遞歸 recursion

• 迭代 iter

• 生成器 generator

from itertools import islicedef fib_while(n): prev = 0 cur = 1 if n in (0,1): return n while n: prev,cur = cur,prev+cur n -= 1 return prevfib_while(10)def fib_recr(n): if n in (0,1): return n else: return fib_recr(n-1) + fib_recr(n-2)class Fib_Iter(object): def __init__(self): self.prev = 0 self.cur = 1 def __iter__(self): return self def __next__(self): self.prev,self.cur = self.cur,self.cur+self.prev return self.prev fib = Fib_Iter()print(next(fib))list(islice(fib,3,5))def fib_ge(): prev = 0 cur = 1 while True: prev,cur = cur,prev+cur yield prevf = fib_ge()print(next(f))list(islice(f,3,5))

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