"Book Notes", "Basic Python Tutorial" chapter I Basic knowledge

Chapter I basic knowledge

2. achieve two-digit integer division: Use the command switch-qnew (? ); use a double slash.
   
   
4. From The future Import Division performs normal division as the calculator.
   
   
6. Exponentiation Operator: 2 * * 3 (8), with function instead of POW (2,3), built-in function
   
   
8. Long integer type: At the end of the number plus L. eg:10000000000000l
   
   
10. Get user input
    
    Input ("hint message:") eg:x = Input ("x:"). The input is a valid Python expression
    Raw_input ("hint message:"), put the user input as raw data into the string.
    
    
12. Built-in function, Standard function--POW, ABS, round: Rounding the floating-point number to the nearest integer value.
    
    
14. module, you need to import it into the Python extension feature with import.
    
    Eg:import math can be used Math.floor (32.9) #向下取整 32.0, ceil () rounding up
    Use INT () to cast to an integral type. Int (Math.floor (32.9)) # 32
    Use the From math import sqrt to use functions directly, without requiring the module name as a prefix.
    The function can be referenced by a variable, Eg:foo = math.sqrt foo (4) is the same as MATH.SQRT (4), the square root is computed, and the result is 2.0
    SQRT (-4) error, cannot process imaginary numbers (end with j), requires import Cmath, uses Cmath.sqrt (-4)
    
    
16. The program automatically ends, you can add Raw_input ("Press") at the end of the code
    
    
18. Concatenation of strings, "hello." + "World"
    
    string printing, str ("Hello,world") #转换为用户看到的字符串 Hello,world
    Repr ("Hello,world") #以合法的python表达式形式表示 ' Hello,world '
    This conversion is useful when printing includes a number variable.
    
    
20. The long string "" or "' does not need to be escaped with a backslash.
    Note: The normal character spans the line: the last character in a row is a backslash, then "\" is the newline escape character
    
    
22. The original string begins with "R", which avoids the use of escape characters. Eg:print r "C:\nowhere"
    
    
24. A Unicode string, stored as a 16-bit Unicode character, and normally stored in 8-bit ASCII code.

"Book Notes", "Basic Python Tutorial" chapter I Basic knowledge