Python练习八

1.获取移动平均值。

def generator():
    sum = 0
    num = 0
    count = 0
    avg = 0
    while 1:
        num = yield avg
        sum += num
        count += 1
        avg = sum / count


avg_g = generator()
avg_g.__next__()
a = avg_g.send(10)
a = avg_g.send(120)
a = avg_g.send(190)
a = avg_g.send(126)
print(a)

2.30以内能被3整除的数，用列表推导式。

ret = [i for i in range(30) if i % 3 == 0]
print(ret)

3.30以内能被3整除的数的平方，用列表推导式。

ret = [i**2 for i in range(30) if i % 3 == 0]
print(ret)

4.找到嵌套列表中名字含有两个‘e’的所有名字。

names = [['Tom', 'Billy', 'Jefferson', 'Andrew', 'Wesley', 'Steven', 'Joe'],
         ['Alice', 'Jill', 'Ana', 'Wendy', 'Jennifer', 'Sherry', 'Eva']]
ret = [name for li in names for name in li if name.count('e') == 2]
print(ret)

5.将一个字典的key和value对调。

mcase = {'a': 10, 'b': 34}
mcase_dic = {mcase[k]: k for k in mcase}
print(mcase_dic)