Python Basics 03-Functions in a detailed

Python functions in a detailed

This content includes:

1. Function
2. Module
3. File operations
4. Exception handling

Function:

• Cognitive functions
• Local variables and global variables
• Explanation of function parameter usage
• function Use Combat

The essence of function is the function of the sub-assembly. For example, we encapsulate a function c=a*a that asks for a 2-time square. We can use this function if we ask for a 2-time change (just for example).

The POW (x, y) in Python is the function that asks for X's Y-square.

Function: Provides the programming efficiency and the scale of the program

Local variables and global variables

A variable has an effective scope, which is scoped.

Global variables: Scope from the beginning of a variable to the last variable on the program to make a global variable

Local variables: Scope only local variables are called local variables "

" " Scope " " a=10def  ABC ():      Global J#用global定义局部变量 changed to globally variable    J=1   Print  (a) ABC ()print(j)

How to use the function:

Function call

# The function definition calls a=1def  ABC ():  #def定义函数 followed by the  function name  and:    print("  ABC") #具体方法, let the function do what, for example: Print out ABC call method: ABC ()
Output ABC ()    

Use of function parameters

Argument: The parameter used for the definition is an argument, and the parameter used when invoked is called an argument

Formal parameters: Just the form of this parameter, no specific value, no value is a formal parameter.

Invoked as an argument.

# formal parameters and arguments def AB (A, B):# The parameters are separated by commas, AB is a formal parameter, there is no actual value    if a>B:        Print  (a)    elif a==B:        Print(A +"=  "+B)    Else:        print(b)

Call AB (+)

Output is 2

Python Basics 03-Functions in a detailed