内置函数-fliter

def is_odd(x):
    return x % 2 == 1
ret = filter(is_odd, [1,4,6,7,9])
print(ret)
for i in ret:
    print(i)

def is_str(s):
    return type(s) == str
ttt = filter(is_str, [1, 'hello'])
print(ttt)
for i in ttt:
    print(i)

from math import sqrt
def fun(x):
    res = sqrt(x)
    return res % 1 == 0

ret = filter(fun,range(1,101))
for i in ret:
    print(i)