Python Strings and variables

Variable:

1. You must assign a value before using the variable;

2. Variable names can be letters, numbers, underscores, but cannot start with numbers;

3. The letters can be uppercase and lowercase, but the case is different, such as Fishc and Fishc are not the same;

4. The equal sign (=) is the meaning of the assignment, the left is the name behind the value can not be written backwards;

5. Variable name as far as possible to professional. Readability is stronger.

Escape characters:

1. If we want to print let ' s go!

>>>let ' s go!

This will be an error.

Use the following method (use the backslash!) )

>>>let\ ' s go!

You can get "let's go!"

or use double quotes:

>>>print ("Let ' s go!")

Let ' s go!

Original string:

But if you want to print "C:\now"

Method One:

>>>str = ' C:\\now '

>>>print (str)

C:\now

But if you want to print "C:\now\haha\miaomiao\bigeng"

Method:

>>>str = R ' C:\now\haha\miaomiao\bigeng '

>>>print (str)

C:\now\haha\miaomiao\bigeng

But there is one problem: if you want to print "C:\now\haha\miaomiao\bigeng\"

The method above will be error-solving:

>>>str = R ' C:\now\haha\miaomiao\bigeng ' + ' \ \ '

>>>print (str)

C:\now\haha\miaomiao\bigeng\

Long string

If you want to print:

 If I love you--
 never learn the birds, 
 to repeat the monotonous song of the shade, 
 also not only like the fountain, 
 perennial send to cool comfort; 
 also more than Xianfeng, increase your altitude, Foil Your Majesty. 
 even daylight. 
 even spring rain. The 
 workaround is as follows: 
  >>>str = "" "  

   If I love you--  
   Never learn the birds of infatuation,   
   　　 
   also more than just a fountain,   
   All year round to bring cool comfort;   
    
   even daylight.   
   even spring rain.   
    
 to get the expected results. 
 < strong> Single Double quote:    
  >>>s6 = ' I realy like "python" !‘     
  >>>print (S6)   

I realy like "python"!
Again:
>>>S5 = "Let ' s go!"
>>>print (S5)

Let ' s go!

Python Strings and variables