Chapter 22. three forms defined function and the return value of the function

Chapter 22. three forms defined function and the return value of the function

I. three forms defined function

1, no function parameter

• 1. When the medium is a defined function argument function body receives an external traditional values, in fact, the variable name
• 2. In the definition phase function, a function of no arguments in parentheses, the function is called with no arguments. Note that: no parameter definition, do not need to pass parameters when calling
• 3. If the logic function body does not depend on the value of the external mass, no parameters have to be defined as a function

del func():
    代码块

2, reference function

• 1. In function definition stage, function parameters in parentheses, known to have a function parameter. Note that: when there is a reference definition, must be passed in parameter is called
• 2. If the function body to rely on external incoming logical value, there have to be defined as a function of parameters

del func(x,y):
    代码块

3, empty function

• When you know the program needs a function, but do not know how to use the code, you can temporarily empty write a function and then to implement other functions, and then back up:

def func():
    pass

II. The return value of the function

1. What is the return value

• Internal code function result obtained through a series of logic

2. Why do we need a return value

• If you need to get the result of the processing program for further processing function, it needs to function must have a return value

3, the return value of the function implemented by return

So what is the return

• 1.return function is a sign of the end, there can be multiple return within a function, to return as long as the execution, the function will stop
• The return value 2.return can return any data type
• Return Value 3.return no limit to the number that can be multiple return values ​​separated by commas
  • Return 0 value: return None
  • It returns a value: The return value is the value itself
  • Return multiple values: The return value is returned as a tuple