函数式编程

print filter(lambda x:x%2==0,(1,2,3,4))
print map(lambda x:x%2==0,(1,2,3,4))
print map(str,(1,2,3,4))
print reduce(lambda x,y:x+y,(1,2,3,4))

def add(x, y):
    return x + y

print reduce(add,(1,2,3,4))