有关python运算符的实例教程,内容非常全面,包括了python算术运算符、python比较运算符、python赋值运算符、python位运算符、python运算符的优先级等常用知识,需要的朋友参考下。
python运算符
例子 4 +5 = 9 ,4和5被称为操作数,"+"号为运算符。  
  
Python语言支持以下类型的运算符:  
算术运算符  
比较(关系)运算符  
赋值运算符  
逻辑运算符  
位运算符  
成员运算符  
身份运算符  
运算符优先级  
学习Python的运算符。  
  
1、Python算术运算符  
以下假设变量a为10,变量b为20:  
  
运算符 描述  实例  
+   加 - 两个对象相加   a + b 输出结果 30  
-   减 - 得到负数或是一个数减去另一个数  a - b 输出结果 -10  
*   乘 - 两个数相乘或是返回一个被重复若干次的字符串    a * b 输出结果 200  
/   除 - x除以y     b / a 输出结果 2  
%   取模 - 返回除法的余数     b % a 输出结果 0  
**  幂 - 返回x的y次幂  a**b 为10的20次方, 输出结果 100000000000000000000  
//  取整除 - 返回商的整数部分   9//2 输出结果 4 , 9.0//2.0 输出结果 4.0 
例子,Python所有算术运算符的操作:  
 
复制代码 代码示例:
#!/usr/bin/python
a = 21  
b = 10  
c = 0  
  
c = a + b  
print "Line 1 - Value of c is ", c  
  
c = a - b  
print "Line 2 - Value of c is ", c   
  
c = a * b  
print "Line 3 - Value of c is ", c   
  
c = a / b  
print "Line 4 - Value of c is ", c   
  
c = a % b  
print "Line 5 - Value of c is ", c  
  
a = 2  
b = 3  
c = a**b   
print "Line 6 - Value of c is ", c  
  
a = 10  
b = 5  
c = a//b   
print "Line 7 - Value of c is ", c 
输出结果:  
Line 1 - Value of c is 31  
Line 2 - Value of c is 11  
Line 3 - Value of c is 210  
Line 4 - Value of c is 2  
Line 5 - Value of c is 1  
Line 6 - Value of c is 8  
Line 7 - Value of c is 2 
2、Python比较运算符  
以下假设变量a为10,变量b为20:  
运算符 描述  实例  
 
==   等于 - 比较对象是否相等   (a == b) 返回 False。  
!=   不等于 - 比较两个对象是否不相等   (a != b) 返回 true.  
<>    不等于 - 比较两个对象是否不相等    (a <> b) 返回 true。这个运算符类似 != 。  
>     大于 - 返回x是否大于y   (a > b) 返回 False。  
<     小于 - 返回x是否小于y。所有比较运算符返回1表示真,返回0表示假。这分别与特殊的变量True和False等价。注意,这些变量名的大写。   (a < b) 返回 true。  
>=    大于等于 - 返回x是否大于等于y。  (a >= b) 返回 False。  
<=    小于等于 - 返回x是否小于等于y。  (a <= b) 返回 true。 
Python所有比较运算符的操作:  
 
复制代码 代码示例:
#!/usr/bin/python  
a = 21  
b = 10  
c = 0  
  
if ( a == b ):  
   print "Line 1 - a is equal to b"  
else:  
   print "Line 1 - a is not equal to b"  
  
if ( a != b ):  
   print "Line 2 - a is not equal to b"  
else:  
   print "Line 2 - a is equal to b"  
  
if ( a <> b ):  
   print "Line 3 - a is not equal to b"  
else:  
   print "Line 3 - a is equal to b"  
  
if ( a < b ):  
   print "Line 4 - a is less than b"   
else:  
   print "Line 4 - a is not less than b"  
  
if ( a > b ):  
   print "Line 5 - a is greater than b"  
else:  
   print "Line 5 - a is not greater than b"  
  
a = 5;  
b = 20;  
if ( a <= b ):  
   print "Line 6 - a is either less than or equal to  b"  
else:  
   print "Line 6 - a is neither less than nor equal to  b"  
  
if ( b >= a ):  
   print "Line 7 - b is either greater than  or equal to b"  
else:  
   print "Line 7 - b is neither greater than  nor equal to b" 
输出结果:  
Line 1 - a is not equal to b  
Line 2 - a is not equal to b  
Line 3 - a is not equal to b  
Line 4 - a is not less than b  
Line 5 - a is greater than b  
Line 6 - a is either less than or equal to b  
Line 7 - b is either greater than or equal to b  
3、Python赋值运算符  
以下假设变量a为10,变量b为20:  
运算符 描述  实例  
 
=   简单的赋值运算符     c = a + b 将 a + b 的运算结果赋值为 c  
+=  加法赋值运算符  c += a 等效于 c = c + a  
-=  减法赋值运算符  c -= a 等效于 c = c - a  
*=  乘法赋值运算符  c *= a 等效于 c = c * a  
/=  除法赋值运算符  c /= a 等效于 c = c / a  
%=  取模赋值运算符  c %= a 等效于 c = c % a  
**= 幂赋值运算符   c **= a 等效于 c = c ** a  
//=  取整除赋值运算符    c //= a 等效于 c = c // a 
Python所有赋值运算符的操作:  
 
复制代码 代码示例:
#!/usr/bin/python  
  
a = 21  
b = 10  
c = 0  
  
c = a + b  
print "Line 1 - Value of c is ", c  
  
c += a  
print "Line 2 - Value of c is ", c   
  
c *= a  
print "Line 3 - Value of c is ", c   
  
c /= a   
print "Line 4 - Value of c is ", c   
  
c  = 2  
c %= a  
print "Line 5 - Value of c is ", c  
  
c **= a  
print "Line 6 - Value of c is ", c  
  
c //= a  
print "Line 7 - Value of c is ", c 
输出结果:  
Line 1 - Value of c is 31  
Line 2 - Value of c is 52  
Line 3 - Value of c is 1092  
Line 4 - Value of c is 52  
Line 5 - Value of c is 2  
Line 6 - Value of c is 2097152  
Line 7 - Value of c is 99864 
4、Python位运算符  
按位运算符是把数字看作二进制来进行计算的。Python中的按位运算法则如下:  
运算符 描述  实例  
 
&    按位与运算符  (a & b) 输出结果 12 ,二进制解释: 0000 1100  
|    按位或运算符  (a | b) 输出结果 61 ,二进制解释: 0011 1101  
^    按位异或运算符     (a ^ b) 输出结果 49 ,二进制解释: 0011 0001  
~    按位取反运算符     (~a ) 输出结果 -61 ,二进制解释: 1100 0011, 在一个有符号二进制数的补码形式。  
<<    左移动运算符   a << 2 输出结果 240 ,二进制解释: 1111 0000  
>>     右移动运算符  a >> 2 输出结果 15 ,二进制解释: 0000 1111 
Python所有位运算符的操作:  
 
复制代码 代码示例:
#!/usr/bin/python  
  
a = 60            # 60 = 0011 1100   
b = 13            # 13 = 0000 1101   
c = 0  
  
c = a & b;        # 12 = 0000 1100  
print "Line 1 - Value of c is ", c  
  
c = a | b;        # 61 = 0011 1101   
print "Line 2 - Value of c is ", c  
  
c = a ^ b;        # 49 = 0011 0001  
print "Line 3 - Value of c is ", c  
  
c = ~a;           # -61 = 1100 0011  
print "Line 4 - Value of c is ", c  
  
c = a << 2;       # 240 = 1111 0000  
print "Line 5 - Value of c is ", c  
  
c = a >> 2;       # 15 = 0000 1111  
print "Line 6 - Value of c is ", c 
输出结果:  
Line 1 - Value of c is 12  
Line 2 - Value of c is 61  
Line 3 - Value of c is 49  
Line 4 - Value of c is -61  
Line 5 - Value of c is 240  
Line 6 - Value of c is 15 
5、Python逻辑运算符  
Python语言支持逻辑运算符,以下假设变量a为10,变量b为20:  
运算符 描述  实例  
 
and  布尔"与" - 如果x为False,x and y返回False,否则它返回y的计算值。    (a and b) 返回 true。  
or  布尔"或" - 如果x是True,它返回True,否则它返回y的计算值。     (a or b) 返回 true。  
not 布尔"非" - 如果x为True,返回False。如果x为False,它返回True。  not(a and b) 返回 false。 
Python所有逻辑运算符的操作:  
 
复制代码 代码示例:
#!/usr/bin/python  
  
a = 10  
b = 20  
c = 0  
  
if ( a and b ):  
   print "Line 1 - a and b are true"  
else:  
   print "Line 1 - Either a is not true or b is not true"  
  
if ( a or b ):  
   print "Line 2 - Either a is true or b is true or both are true"  
else:  
   print "Line 2 - Neither a is true nor b is true"  
  
  
a = 0  
if ( a and b ):  
   print "Line 3 - a and b are true"  
else:  
   print "Line 3 - Either a is not true or b is not true"  
  
if ( a or b ):  
   print "Line 4 - Either a is true or b is true or both are true"  
else:  
   print "Line 4 - Neither a is true nor b is true"  
  
if not( a and b ):  
   print "Line 5 - a and b are true"  
else:  
   print "Line 5 - Either a is not true or b is not true" 
输出结果:  
Line 1 - a and b are true  
Line 2 - Either a is true or b is true or both are true  
Line 3 - Either a is not true or b is not true  
Line 4 - Either a is true or b is true or both are true  
Line 5 - a and b are true 
6、Python成员运算符  
除了以上的一些运算符之外,Python还支持成员运算符,测试实例中包含了一系列的成员,包括字符串,列表或元组。  
  
运算符 描述  实例  
 
in   如果在指定的序列中找到值返回True,否则返回False。   x 在 y序列中 , 如果x在y序列中返回True。  
not in  如果在指定的序列中没有找到值返回True,否则返回False。 x 不在 y序列中 , 如果x不在y序列中返回True。 
Python所有成员运算符的操作:  
 
复制代码 代码示例:
#!/usr/bin/python  
  
a = 10  
b = 20  
list = [1, 2, 3, 4, 5 ];  
  
if ( a in list ):  
   print "Line 1 - a is available in the given list"  
else:  
   print "Line 1 - a is not available in the given list"  
  
if ( b not in list ):  
   print "Line 2 - b is not available in the given list"  
else:  
   print "Line 2 - b is available in the given list"  
  
a = 2  
if ( a in list ):  
   print "Line 3 - a is available in the given list"  
else:  
   print "Line 3 - a is not available in the given list" 
输出结果:  
Line 1 - a is not available in the given list  
Line 2 - b is not available in the given list  
Line 3 - a is available in the given list 
7、Python身份运算符  
身份运算符用于比较两个对象的存储单元  
运算符 描述  实例  
 
is   is是判断两个标识符是不是引用自一个对象    x is y, 如果 id(x) 等于 id(y) , is 返回结果 1  
is not  is not是判断两个标识符是不是引用自不同对象     x is not y, 如果 id(x) 不等于 id(y). is not 返回结果 1 
Python所有身份运算符的操作:  
 
复制代码 代码示例:
#!/usr/bin/python  
  
a = 20  
b = 20  
  
if ( a is b ):  
   print "Line 1 - a and b have same identity"  
else:  
   print "Line 1 - a and b do not have same identity"  
  
if ( id(a) == id(b) ):  
   print "Line 2 - a and b have same identity"  
else:  
   print "Line 2 - a and b do not have same identity"  
  
b = 30  
if ( a is b ):  
   print "Line 3 - a and b have same identity"  
else:  
   print "Line 3 - a and b do not have same identity"  
  
if ( a is not b ):  
   print "Line 4 - a and b do not have same identity"  
else:  
   print "Line 4 - a and b have same identity" 
输出结果:  
Line 1 - a and b have same identity  
Line 2 - a and b have same identity  
Line 3 - a and b do not have same identity  
Line 4 - a and b do not have same identity  
8、Python运算符优先级  
以下表格列出了从最高到最低优先级的所有运算符:  
运算符 描述  
 
**  指数 (最高优先级)  
~ + -   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 
Python所有运算符优先级的操作:  
 
复制代码 代码示例:
#!/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 
输出结果:  
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