什么是运算符？
本章节主要说明Python的运算符。举个简单的例子 4 +5 = 9 。 例子中，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
接下来让我们一个个来学习Python的运算符。
Python算术运算符
以下假设变量a为10，变量b为20：
以下实例演示了Python所有算术运算符的操作：
#!/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
以上实例输出结果：
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
Python比较运算符
以下假设变量a为10，变量b为20：
以下实例演示了Python所有比较运算符的操作：
#!/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"
以上实例输出结果：
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
Python赋值运算符
以下假设变量a为10，变量b为20：
以下实例演示了Python所有赋值运算符的操作：
#!/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
以上实例输出结果：
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
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：
& ，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
>以下实例演示了Python所有位运算符的操作：
>#!/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
以上实例输出结果：
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
