浅析python函数式编程

listDemo = [1, 2, 3, 4, 5]
new_list = map(lambda x: x * 2, listDemo)
print(list(new_list))

listDemo = [1, 2, 3, 4, 5]
new_list = filter(lambda x: x % 2 == 0, listDemo)
print(list(new_list))

import functools
listDemo = [1, 2, 3, 4, 5]
product = functools.reduce(lambda x, y: x * y, listDemo)
print(product)

>a = [1,2,3]
>b = [4,5,6]
>c = [4,5,6,7,8]
>zipped = zip(a,b) # 打包为元组的列表
[(1, 4), (2, 5), (3, 6)]
>zip(a,c)     # 元素个数与最短的列表一致
[(1, 4), (2, 5), (3, 6)]
>zip(*zipped)   # 与 zip 相反，可理解为解压，返回二维矩阵式
[(1, 2, 3), (4, 5, 6)]

> L=[('b',2),('a',1),('c',3),('d',4)]
> sorted(L, key=lambda x:x[1])        # 利用key
[('a', 1), ('b', 2), ('c', 3), ('d', 4)]

> students = [('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]
> sorted(students, key=lambda s: s[2])      # 按年龄排序
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]