Python运算符多数与C/C++/Java类似,但有两个不一样。“//”表示求商,“**”表示求幂
a = 10
b = 3
x = a / b
y = a // b
z = a**b
print x,y,z
c = float(b)
m = a / c
n = a // c
print m,n
运行结果:
3 3 1000
3.33333333333 3.0
in : 如果在指定的序列中找到值返回 True,否则返回 False not in : 如果在指定的序列中没有找到值返回 True,否则返回 False
a = 1
b = 20
list = [1, 2, 3, 4, 5 ];
if ( a in list ):
print "a is in the list"
else:
print "a is not in the list"
if ( b not in list ):
print "b is not in the list"
else:
print "b is in the list"
运行结果:
a is in the list
b is not in the list
is : 判断两个标识符是不是引用自一个对象 is not : 判断两个标识符是不是引用自不同的对象
a = 20
b = 20
if ( a is b ):
print "a and b is the same object"
else:
print "a and b is not the same object"
if ( a is not b ):
print "a and b is not the same object"
else:
print "a and b is the same object"
b = 30
if ( a is b ):
print "a and b is the same object"
else:
print "a and b is not the same object"
运行结果:
a and b is the same object
a and b is the same object
a and b is not the same object
is与==的区别 is 用于判断两个变量引用对象是否为同一个, == 用于判断引用变量的值是否相等
>>> a = [1, 2, 3]
>>> b = a
>>> b is a
True
>>> b == a
True
>>> b = a[:]
>>> b is a
False
>>> b == a
True
说明,b =a[:],这里冒号前面和后面都没有数字,表示取a的第一个元素到最后一个元素,放到另一个对象b里。所以b与a里的数据相同,但不是同一个对象。
运算符 |描述
-------------------------|---------------------------------------------------
() |括号(最高优先级)
** |指数
~ + - |按位翻转, 一元加号和减号 (最后两个的方法名为 +@ 和 -@)
* / % // |乘,除,取模和取整除
+ - |加法减法
>> << |右移,左移运算符
& |位 'AND'
^ |位运算符
<= < > >= |比较运算符
<> == != |等于运算符
= %= /= //= -= += *= **= |赋值运算符
is, is not |身份运算符
in, not in |成员运算符
not, or, and |逻辑运算符