Python anonymous function--lambda expression

If the function to be defined is simple, a return statement can be done and can be defined using a lambda expression,

The syntax for a lambda expression is as follows:

Lambda parameters:expression

Lambda expressions do not contain return statements, and you can use lambda expressions wherever functions are used as parameters or return values, and the benefits of lambda functions are:

• Easy and Handy
• You can not name the function, some places do not need to reuse the function, essentially do not need to give the function to think of a name

The following example 1 takes the function defined by the lambda expression as a parameter to the built-in function filter.

Example 1. To use a lambda function as a parameter

>>> L = [1, 2, 3, 4, 5, 6, 7, 8, 9]>>> low = 3>>> High = 7>>> Filter (lambda x, L=low, H=HIGH:H>X>L), L) [4, 5, 6]

Example 1 directly to the defined lambda function as a parameter to the built-in function filter, you can also assign a lambda function to an identifier, convenient for future calls:

Example 2. Invoking a lambda function

>>> f = lambda x, y, z:x + y-z>>> f (1, 2, 3) 0

　　

Python anonymous function--lambda expression