Python Lambda Definition and Application

In Python, lambda is a simple way to define anonymous functions, allowing us to define simple functions without using the def keyword.

The syntax for a lambda function is as follows:

lambda arguments: expression

Where arguments represents the function's parameters, which can be zero or more and are separated by commas; expression represents the return value of the function, which can be any expression.

For example, the code below defines a lambda function that accepts two parameters and returns their sum:

sum = lambda x, y: x + y

lambda functions are typically used to define simple functions, such as sorting rules, filtering conditions, or mapping functions in operations like sorting, filtering, or mapping. lambda functions are usually concise and can complete function definition and invocation in a single line of code.

It should be noted that lambda functions can only define simple function bodies. If the function body is complex, it is recommended to use the def keyword to define named functions.