python迭代器

---

title: python迭代器
data: 2018-4-7
categories:

• python
  tags:
• python

---

容器(container)、可迭代对象(iterable)、迭代器(iterator)、生成器(generator)、

列表(list)、集合(set)、字典推导式(dict comprehension)

class Fibs:
    def __init__(self):
        self.a = 0
        self.b = 1
    def __iter__(self):
        return self
    def __next__(self):
        self.a, self.b = self.b, self.a + self.b
        return self.a

fib = Fibs()

for i in fib:
    if i < 10:
        print(i, end=" ")
    else:
        break

结果：

1 1 2 3 5 8 

class squares:
    def __init__(self, start, stop):
        self.flag = start - 1
        self.value = self.flag
        self.stop = stop
    def __iter__(self):
        self.value = self.flag
        return self
    def __next__(self):
        if self.value == self.stop:
            raise StopIteration
        self.value += 1
        return self.value
 
a = squares(1, 5)
b = squares(1, 5)
s = 0
while s <= 41:
    for i in a:
        s = s + i
        print(s, end=" ")

结果：

1 3 6 10 15 16 18 21 25 30 31 33 36 40 45

class test():
    def __init__(self,data=1):
        self.data = data

    def __iter__(self):
        return self
    def __next__(self):
        if self.data > 5:
            raise StopIteration
        else:
            self.data+=1
            return self.data

for item in test(3):
    print(item, end=" ")

结果：

4 5 6