Note 1 for <Pratical Programming : An Introduction to Computer Science Using Python 3>

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Book Imformation : <Pratical Programming : An Introduction to Computer Science Using Python 3> 2nd Edtion

Author : Paul Gries,Jennifer Campbell,Jason Montojo

Page : Chapter 1 and Chapter 2.1-2.2

 

1.every computer runs operating system,which it‘s the only program on the computer that‘s allowed direct access to the hardware(硬體).

or more complicate(add another layer between the programmer and the hardware) :

2.two ways to use the Python interpreter(解譯器) : 

(1).execute a saved Python program with .py extension(擴充，尾碼)

(2).using a Python shell(殼，命令解析器)

3.the >>> symbol is called a prompt(提示),prompting you to type something

4.the result of interger division has a decimal point even is a whole number :

1 >>> 5 / 22 2.53 >>> 4 / 24 2.0

5.when the operands (運算元) are int and float,Python automatically convert the int into a float :

1 >>> 17.0 - 102 7.03 >>> 17 - 10.04 7.0

and you can omit zero like ‘17.’ (but most people think it is a bad idea) 

6.integer division,modulo(模數) 

1 >>> 53 // 24 2 23 >>> 53 % 244 5

//：整除

when the operands are negative or float,it takes the floor(向下取整) of the result.

1 >>> -17 // 10 2 -23 >>> 17 // 104 1

1 >>> 3.5 // 1.02 3.03 >>> 3 // 1.14 2.05 >>> 3.3 // 16 3.0

when using modulo,the sign of the result matches the divisor(除數)

定義：a % b = a - n*b，n為不超過a/b的整數

1 >>> -17 % 102 33 >>> 17 % -104 -3

7.exponentiation(取冪)：**

1 >>> 2 ** 32 83 >>> 3 ** 34 27

8.binary operators(雙目運算子),unary operators(單目運算子)

+、-、*、/：binary operators

-(nagetive)：unary operators

1 >>> -52 -53 >>> --54 55 >>> ---56 -5

 

Note 1 for <Pratical Programming : An Introduction to Computer Science Using Python 3>