py-day4 python filter函数

filter函数：遍历序列中的每个元素，判断每个元素得到布尔值，如果是True则留下

# 例子：条件筛选

name =['m_xiaoli','zhangfei','m_xiaoma','m_wangyun']

ret = []

def test(name):

    for i in name:

        if not i.startswith("m"):

            ret.append(i)

    return ret

print(test(name))

['zhangfei']

def test1(array):       # (最好不要用全局变量，自己定义一个变量如左)

    for i in array:

        if not i.startswith("m"):

            ret.append(i)

    return ret

print(test1(name))

['zhangfei']

# 在写程序时尽量不要把函数写死，

name =['xiaoli_d','zhangfei','xiaoma_d','m_wangyun']

ret = []

def qu_d(n):　　　　　　　　　　　　# 定义灵活的函数

    return n.endswith('_d')

def qu_m(w):

    return w.startswith('m_')

def test(func,array):

    for i in array:

        if not func(i):

            ret.append(i)

    return ret

ret = test(qu_d,name)

ref = []

def test2(func2,array2):

    for p in array2:

        if not func2(p):

            ref.append(p)

    return ref

ref = test2(qu_m,name)

print('不是_d结尾的：',ret)

print('不是m_开头的：',ref)

不是_d结尾的： ['zhangfei', 'm_wangyun']

不是m_开头的： ['xiaoli_d', 'zhangfei', 'xiaoma_d']

 #不定义，用lamnda函数也可以

name =['xiaoli_d','zhangfei','xiaoma_d','m_wangyun']

ret = []

def test(func,array):

    for i in array:

        if not func(i):

            ret.append(i)

    return ret

ret = test(lambda i:i.endswith('_d'),name)

print('不是_d结尾的：', ret)

不是_d结尾的： ['zhangfei', 'm_wangyun']

# 终极版 filter函数

name =['xiaoli_d','zhangfei','xiaoma_d','m_wangyun']

ret = []

def test(func,array):

    for i in array:

        if not func(i):

            ret.append(i)

    return ret

ret = filter(lambda i:not i.endswith('_d'),name)

print('不是_d结尾的：',list(ret))

不是_d结尾的： ['zhangfei', 'm_wangyun']