讲解Python中运算符使用时的优先级

例如x=7 + 3* 2;这里，x被赋值13，而不是20，因为运算符*的优先级比+更高，所以它首先乘以3 * 2，然后加7。

这里，具有最高优先级运算符出现在表格上方，那些最低的显示在底部。在一个表达式，更高的优先级运算符将首先计算。

例如：

试试下面的例子来理解Python编程语言可供选择的运算符优先级：

#!/usr/bin/python

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

当执行上面的程序，它会产生以下结果：

Value of (a + b) * c / d is 90
Value of ((a + b) * c) / d is 90
Value of (a + b) * (c / d) is 90
Value of a + (b * c) / d is 50