Python入门示例系列30 Python运算符优先级和结合性

 

 

表 1 Python 运算符优先级和结合性一览表

运算符说明	Python运算符	优先级	结合性	优先级顺序
小括号	( )	19	无	高 ︿  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |   |  | 低
索引运算符	x[i] 或 x[i1: i2 [:i3]]	18	左
属性访问	x.attribute	17	左
乘方	**	16	右
按位取反	~	15	右
符号运算符	+（正号）、-（负号）	14	右
乘除	*、/、//、%	13	左
加减	+、-	12	左
位移	>>、<<	11	左
按位与	&	10	右
按位异或	^	9	左
按位或	|	8	左
比较运算符	==、!=、>、>=、<、<=	7	左
is 运算符	is、is not	6	左
in 运算符	in、not in	5	左
逻辑非	not	4	右
逻辑与	and	3	左
逻辑或	or	2	左
逗号运算符	exp1, exp2	1	左

 

 示例：

a = 20
b = 10
c = 15
d = 5
e = 0

e = (a + b) * c / d       #( 30 * 15 ) / 5
print("Value of (a + b) * c / d is ",  e)

e = ((a + b) * c) / d     # (30 * 15 ) / 5
print("Value of ((a + b) * c) / d is ",  e)

e = (a + b) * (c / d);    # (30) * (15/5)
print("Value of (a + b) * (c / d) is ",  e)

e = a + (b * c) / d;      #  20 + (150/5)
print("Value of a + (b * c) / d is ",  e)

输出结果：

Value of (a + b) * c / d is  90.0
Value of ((a + b) * c) / d is  90.0
Value of (a + b) * (c / d) is  90.0
Value of a + (b * c) / d is  50.0

 

 

REF

https://www.tutorialspoint.com/python/operators_precedence_example.htm#:~:text=Python%20Operators%20Precedence%20Example%20%20%20%20Operator,Addition%20and%20subtraction%20%209%20more%20rows%20

http://c.biancheng.net/view/2190.html

https://pythongeeks.org/python-operator-precedence/