一、lambda函数的语法
lambda语句中，冒号前是参数，可以有0个或多个，用逗号隔开，冒号右边是返回值。lambda语句构建的其实是一个函数对象。
1》无参数：
f = lambda:'Hello python lambda' f() #'Hello python lambda'
2》有参数，无默认值
f = lambda x,y: x*y f(6,7) #42
3》有参数，有默认值
f = lambda x=5, y=8: x*y f() #40 f(5,6) #30
4》和map, reduce, filter连用
foo = [2, 18, 9, 22, 17, 24, 8, 12, 27] print filter(lambda x: x % 3 == 0, foo)#python 2.x list( filter(lambda x: x % 3 == 0, foo) )#python 3.x #[18, 9, 24, 12, 27] print map(lambda x: x * 2 + 10, foo)#python 2.x list( map(lambda x: x * 2 + 10, foo) )#python 3.x #[14, 46, 28, 54, 44, 58, 26, 34, 64] from functools import reduce#python 3.x need import reduce reduce(lambda x, y: x + y, foo) #139