python variables and objects

First, the exit window of three methods: 
    1.ctrl + z, the Enter 
    2.quit () 
    3.exit () 
Second, view the current version number python: python --version 
three, python variables and objects: 
variable naming: 
    1. Composition elements: letters, underscores, numbers 
    2. Do not start with a number 
    3. It was generally variable names recommended by the letters 
    4. see name known Italian - English 
IV: see keyword 
Import keyword 
Print (keyword.kwlist)

# Slice, sequence type

= STR 'name IS Tom' 

Print (STR [. 5: + 2. 5]) containing the left and excluding #

Print (STR [-3:]) 
Print (STR [:: -. 1]) # flashback