关于map()与filter()

def f1(a):
    if a == 3:
        pass
    else:
        return a*a
li = [1,2,3,4]
for i in filret(f1,li)
　　print(i)

def f1(a):
    if a == 3:
        pass
    else:
        return a*a
li = [1,2,3,4]
# for i in filter(f1,li):
#     print(i)

for i in map(f1,li):
    print(i)