Python's function learning

Functions and procedures are functions that have no return value, both of which can be called

in python , the function return value is The value after return, and the procedure return value is None

Programming: Object-oriented, process-oriented, functional programming

Process-oriented programming: It is a small process defined by a def that is stitched together into a piece

Functional Programming:F =2x The mathematical function has an x, there will be a corresponding f - value such as:lisp, Erlang

For example , a function like the Python language is a true or false judgment, that is, an x does not necessarily correspond to an F

The following example: To calculate (1+2) *3-4

Traditional way:

var a =1+2;

var b =a*3;

var c=b-4;

Functional programming requires functions, which we can define as different functions, and then write the following styles:

var result =subtract (ultiply (Add (1+2), 3), 4)

This is functional programming.

Three great benefits of using functions:

reusability, consistency, and extensibility of code

returned value return

returns 0 values ( no return value ): Return to none

returns 1 values: returned as object (all data types in python are objects)

return multiple values : returns a tuple(tuple)

If this is: the return function now results in the address of the function

writing python files from Linux

Way:

First: Create a file vim test.py

Next: Write a program in the Vim file editor

Eg:def test2 (X,*args,**kwargs): print (x)
Print (args)
Print (Kwargs)
Test2 (" haha ", 4,sex = "F", name = "Zhangsan")

Then : Press:WQ Complete program writing

finally : results can be run by writing python test.py in terminal

The process of writing a function:

Define and write the function first

In writing the arguments of a function for delivery

Run the process: read the actual parameters first, and then pass the actual parameters to the function for processing

# Local Variables but for lists, dictionaries, collections, classes can be changed in local variables
School = "Oldboy" # global variable
def test4 (name):
Global School # The keyword allows you to change globals within a function
School = "Mage Linux"
Name = "Lisi" # Default: This function is the scope of the variable scope can be changed by the global keyword
Print (Name,school)

Name = "Zhangsan"
TEST4 (name)
Print (name)
Print (school)

Python's function learning