Python = = "function

A. Ask a question, why do you have a function?

1. Make the program simple

2. Improve the readability of your code

Definition of the function:

def function name (parameter 1, parameter 2):    Comment of---function---    print (' function body ')    return ' value '

Call to function:

return value = function name (parameter 1, parameter 2)

Parameters of the function: arguments and formal arguments. (Class two)

Argument: The value of the parameter passed in when the function is called.

Formal parameter: The name of the parameter defined when the function is defined.

Parameters: Divided into three categories.

1. The parameter can be any data type. 2. You can pass 0 or more parameters.

Position parameters:

Defining parameters sequentially

Default parameters:

First, do not set the default parameter for a mutable type, and you can set a default parameter for a parameter that has little variation.

If passed, overrides the default value of the default value is set before the function definition is OK.

Dynamic Parameters:

   *args **kwargs

Arguments to invoke a function: pass the parameter by location:

Def My_max (A, b):    print (A, b) My_max (10,20)

Follow the key word parameters:

def My_max (    A, A, b): Print (A, A, My_max (a), a=20)

The return value of the function:

Keyword for return value: return

The function of return:

1. Ending the execution of a function

2. Return the value you want to return

Two cases of return value:

One. The return value is None

There are three cases where the return value of the function is none.

1. Do not write the return value

2. Write only a return

3.return None (almost unused)

1. Do not write the return valuereturndeffunc1 (): a= 111b= [A]ret=func1 ()Print(ret)#2.returndefFunc2 (): a= 111b= [A]    returnret=Func2 ()Print(ret)#3. Returndeffunc3 (): a=111b= [A]    returnNoneret=func3 ()Print(ret) The return value of these three cases is none. 

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Two. The return value is not none

1. Returns a value

Receive with a variable

2. Return multiple values

Received with a variable, the result is a tuple

There are multiple return values that are received in the number of variables.

　　　　

　　

Python = = "function