Introduction to module usage and object orientation in Python

1. Module Use 

Module:

• Modular Pyth1.on The basic way of organizing code

• A python script can run on its own, or it can be imported into another script, which we call Modules (module) when the script is imported and run.

• All the points P for the file can be imported as a module

• The module name is the same as the file name of the script, for example, we have written a script named HELLO.PV and can import it in another script with import hello.py

Package:

Python modules can be organized into packages by directory

Steps to create a package:

Create a directory with the name of the package name, create a __init__.py file under that directory, and place the script file or compiled extensions and sub-packages in the directory as needed

Grammar:

Import pack.m1,pack.m2,pack.m3

Sys.path

Example:

In [1]: import sys

In [2]: sys.path

OUT[2]:

['',

'/usr/bin ',

'/usr/lib64/python27.zip ',

'/usr/lib64/python2.7 ',

'/usr/lib64/python2.7/plat-linux2 ',

'/usr/lib64/python2.7/lib-tk ',

'/usr/lib64/python2.7/lib-old ',

'/usr/lib64/python2.7/lib-dynload ',

'/usr/lib64/python2.7/site-packages ',

'/usr/lib64/python2.7/site-packages/gtk-2.0 ',

'/usr/lib/python2.7/site-packages ',

'/usr/lib/python2.7/site-packages/ipython/extensions ',

'/root/.ipython ']

VIM/ROOT/.BASHRC

Finally add an export pythonpath=/root/library

Successfully added to the Python environment variable

In [1]: import sys

In [2]: sys.path

OUT[2]:

['',

'/usr/bin ',

'/root/library ',

'/usr/lib64/python27.zip ',

'/usr/lib64/python2.7 ',

'/usr/lib64/python2.7/plat-linux2 ',

'/usr/lib64/python2.7/lib-tk ',

'/usr/lib64/python2.7/lib-old ',

'/usr/lib64/python2.7/lib-dynload ',

'/usr/lib64/python2.7/site-packages ',

'/usr/lib64/python2.7/site-packages/gtk-2.0 ',

'/usr/lib/python2.7/site-packages ',

'/usr/lib/python2.7/site-packages/ipython/extensions ',

'/root/.ipython ']

Scripts that can be called by other scripts:

#!/usr/bin/env python

#

def wordCount (s):

chars = Len (s)

words = Len (S.split ())

lines = s.count (' \ n ')

Print Lines,words,chars

if __name__== ' __main__ ': #设置后, the functions within this script can be called by other scripts test.py

s = open ('/etc/passwd '). Read ()

WordCount (s)

#

[Email protected] 20180109]# python words.py

27 52 1324

[Email protected] 20180109]# wc/etc/passwd

1324/etc/passwd

import words.py in test.py:

[Email protected] 20180109]# cat test.py

#!/usr/bin/env python

Import words

#

s= "" "Hello World Python" "

Words.wordcount (s)

[email protected] 20180109]# python test.py

27 52 1324

[[email protected] 20180109]# ls

test.py words.py words.pyc # # #调用words后自动生成编译的文件.

Modules and Packages:

A module is a script file that can be imported

Packages are directory-organized modules and sub-packages, with __init__.py files in the directory, which can store information about the package.

Syntax for importing modules and packages:

Import,import as

From ... import ...

From the individual name:

2. Object-Oriented Introduction

Classes and objects: Two important concepts in object-oriented

Class: Is an object's abstraction of things, such as human \ Ball

Object: Is an instance of a class, such as football \ Basketball

Example Description:

Balls can abstract the characteristics and behavior of the ball and then instantiate a real sphere.

Why object-oriented?

The main idea of object-oriented is

• Packaging

• Inherited

• Polymorphic

This idea solves more complex projects and is easier to maintain.

Python class definition

Class definition:

Classes combine the required variables and functions, which are called "encapsulation",

Class A (object):

Structure of the class:

Class name

Member Variables-Properties

member functions-Methods

The creation of a class

Class MyClass (object):

def fun (self):

Print ("I am Function")

There is at least one parameter in the class's method self

Examples of class scripts:

class People (object):

color = ' Yellow '

def think (self):

Self.color = "BLACK"

print "I am a%s"% Self.color

print ("I am a Thinker")

ren = people ()

Print Ren.color

Ren.think ()

Introduction to module usage and object orientation in Python