Python Basics 1

The difference between Python2 and 3:

1. Character encoding

In python2.7

# _*_coding:utf-8_*_ Print ' Hello '

python3.5 doesn't need to be bothered by annoying character encodings.

Print (' hello ')

2.print

Need to add () in python3.5

3. Renaming some libraries

Old name New name

_winreg winreg

Configparser Configparser

Copy_reg Copyreg

Queue queue

Socketserver Socketserver

Markupbase _markupbase

Repr Reprlib

Test.test_support Test.support

Second, Python installs Linux installed Python3.5wget Https://www.python.org/ftp/python/3.5.2/Python-3.5.2.tgztar XF python-3.5.0.tgz
CD Python-3.5.0
./configure--prefix=/usr/local--enable-shared
Make
Make install
Ln–s/usr/local/bin/python3/usr/bin/python3 (soft link) Windows

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1、下载安装包    https://www.python.org/downloads/2、安装    默认安装路径：C:\python273、配置环境变量    【右键计算机】--》【属性】--》【高级系统设置】--》【高级】--》【环境变量】--》【在第二个内容框中找到 变量名为Path 的一行，双击】 --> 【Python安装目录追加到变值值中，用 ； 分割】    如：原来的值;C:\python27，切记前面有分号

Third, Hello World procedure

Create a file under Linux called hello.py, and enter

#!/usr/bin/env python

Print ("Hello World")

So, execute:. /hello.py Can.

PS: Need to give hello.py execute permission before execution, chmod 755 hello.py

Comments:

When the line stares: # is annotated content

Multiline Comment: "" "Annotated Content" ""

Iv. user Input

#!/usr/bin/env python

#_*_coding:utf-8_*_   #name = raw_input("What is your name?") #only on python 2.x name  =  input ( "What is your name?" )#3.5 print ( "Hello "  +  name )when entering a password, if you want to be invisible, you need to take advantage of the Getpass method in the Getpass module, namely: #!/usr/bin/env python # -*- coding: utf-8 -*-    import  getpass    # 将用户输入的内容赋值给 name 变量 pwd  =  getpass.getpass( "请输入密码：" )    # 打印输入的内容 print (pwd)Note: Can only be used on LinuxFive, module

(1) Sys

　　import  sys print (sys.argv)     #输出   $ python test.py helo world   [ ‘test.py‘ ,  ‘helo‘ ,  ‘world‘ ]   #把执行脚本时传递的参数获取到了

(2) OS

Import OS

　　os.system("df -h") #调用系统命令

(3) Tab Completion module

1#!/usr/bin/env python2#python startup file3ImportSYS4ImportReadLine5ImportRlcompleter6Importatexit7ImportOS8#Tab Completion9 Readline.parse_and_bind ('Tab:complete')10#History FileHistfile = Os.path.join (os.environ['HOME'],'. Pythonhistory')12Try:13readline.read_history_file (histfile)14exceptIOError:15Pass16Atexit.register (Readline.write_history_file, Histfile)17delOS, Histfile, ReadLine, Rlcompleter

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Python Basics 1