python学习-29 map函数-filter函数

movie_person = ['小红','小明','小王','富豪_sb','美女_sb']

def filter_test(array):
    ret = []
    for i in array:
        if not i.startswith('小'):   # 以‘小’开头的
            ret.append(i)
    return  ret
print(filter_test(movie_person))



def filter_test(array):
    res = []
    for i in array:
        if not i.endswith('sb'):   # 以‘sb’结尾的
            res.append(i)
    return  res
print(filter_test(movie_person))

运行结果：

['富豪_sb', '美女_sb']
['小红', '小明', '小王']

Process finished with exit code 0

或另一种简单的方法：

movie_person = ['小红','小明','小王','富豪_sb','美女_sb']

def filter_test(func,array):
    ret = []
    for i in array:
        if not func(i):   
            ret.append(i)
    return  ret

res = filter_test(lambda x:x.endswith('sb'),movie_person)   # 以‘sb’结尾的
print(res)

运行结果：

['小红', '小明', '小王']

Process finished with exit code 0

reduce函数

1.加法和乘法（两种方法）

from functools import reduce            # 调用 reduce函数

num_1 = [1,2,3,4,5,6,7,8,9,100]

def reduce_test(array):
    res = 0
    for num in array:
        res += num
    return res
print(reduce_test(num_1))


def reduce_test(func,array):
    res = array.pop(0)            # 将列表的值一个一个传值
    for num in array:
        res =func(res,num)
    return res
print(reduce_test(lambda  x,y:x*y,num_1))     # 用lambda 进行乘法运算

运行结果：

145
36288000

Process finished with exit code 0

2.传一个初始值

from functools import reduce            # 调用 reduce函数

num_1 = [1,2,3,4,5,6,7,8,9,100]

def reduce_test(func,array,init = None):
    if init is None:
        res = array.pop(0)
    else:
        res = init
    for num in array:
        res = func(res,num)
    return res
print(reduce_test(lambda x,y:x*y,num_1,100))     # 传了一个初始值100，以100开始乘以列表里的每个数

运行结果：

3628800000

Process finished with exit code 0