html5 自适应网站,建立网站的教学书籍,wordpress流动图片,免费域名网站创建Python 运算符
什么是运算符#xff1f;
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#xff0c;4和5被称为操作数#xff0c;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#xff08;关系#xff09;运算符
赋值运算符
…Python 运算符
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
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
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
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。
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
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
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
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
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
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Falsex 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。
以下实例演示了Python所有逻辑运算符的操作
#!/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 - Either a is not true or b is not true or both are not true
else:
print Line 5 - a and b are true
以上实例输出结果
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 - Either a is not true or b is not true or both are not true
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。
以下实例演示了Python所有成员运算符的操作
#!/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
以上实例输出结果
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
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
以下实例演示了Python所有身份运算符的操作
#!/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
以上实例输出结果
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
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
以下实例演示了Python所有运算符优先级的操作
#!/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
以上实例输出结果
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
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