记录学习python时的问题（一）

看python官方文档时看到

lambda expression

Small anonymous functions can be created with the 

lambda

 keyword. This
function returns the sum of its two arguments: 

lambda a, b: a+b

.
Lambda functions can be used wherever function objects are required. They are syntactically restricted to a single expression. Semantically, they are just syntactic sugar for a normal function definition. Like nested function definitions, lambda functions
can reference variables from the containing scope:

>>> def make_incrementor(n):
...     return lambda x: x + n
...
>>> f = make_incrementor(42)
>>> f(0)
42
>>> f(1)
43

这个例子看不懂，故在解释器中运行了 make_incrementor(42)  结果发现这是个函数，于是恍然大悟，原来

return lambda x: x + n

返回一个匿名函数，x是传入的参数，x + n 是返回值