Python技巧之拉姆达（Lambda）函数

Python中的‘lambda’关键字提供了一个便捷的途径去声明短小并匿名的函数。

1# The lambda keyword in Python provides a
2# shortcut for declaring small and 
3# anonymous functions:
4
5>>> add = lambda x, y: x + y
6>>> add(5, 3)
78
8
9# You could declare the same add() 
10# function with the def keyword:
11
12>>> def add(x, y):
13...     return x + y
14>>> add(5, 3)
158
16
17# So what's the big fuss about?
18# Lambdas are *function expressions*:
19>>> (lambda x, y: x + y)(5, 3)
208
21
22# • Lambda functions are single-expression 
23# functions that are not necessarily bound
24# to a name (they can be anonymous).
25
26# • Lambda functions can't use regular 
27# Python statements and always include an
28# implicit `return` statement.

Lambda函数是单一表达式函数，即无需绑定名称。

Lambda函数不能使用常规的语句，通常包含一个隐式的返回语句。