Python - 基本操作符

运算符是可以操纵操作数值的构造，考虑表达式4 + 5 =9。这里，4和5称为操作数，而+称为运算符。

Python语言支持以下类型的运算符。

• 算术运算符
• 比较运算符
• 分配运算符
• 逻辑运算符
• 按位运算符

让无涯教程一一看一下所有运算符。

链接：https://www.learnfk.comhttps://www.learnfk.com/python/python-basic-operators.html

来源：LearnFk无涯教程网

算术运算符

假设变量a=10，变量b=20，则-

假设变量a=21而变量b=10，则-

#!/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

当您执行上述程序时，它将产生以下结果-

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

比较运算符

这些运算符比较它们两侧的值并确定它们之间的关系。它们也称为关系运算符，假设变量a=10，变量b=20，则-

假设变量a=10，变量b=20，则-

#!/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"

当您执行上述程序时，它将产生以下结果-

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

赋值运算符

假设变量a=10，变量b=20，则-

假设变量a=10，变量b=20，则-

#!/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

当您执行上述程序时，它将产生以下结果-

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

按位运算符

按位运算符对位进行运算并执行逐位运算。假设a=60;并且b=13;现在以二进制格式，它们将如下所示-

a=0011 1100

b=0000 1101

-----------------

a&b=0000 1100

a | b=0011 1101

a ^ b=0011 0001

〜a=1100 0011

Python语言支持以下Bitwise运算符

#!/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

当您执行上述程序时，它将产生以下结果-

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

逻辑运算符

Python语言支持以下逻辑运算符。假设变量a=10，变量b=20

Membership运算符

Python的Membership运算符会测试序列中的成员运算，如字符串，列表或元组。

#!/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"

当您执行上述程序时，它将产生以下结果-

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

Identity 运算符

Identity 运算符比较两个对象的内存位置。

#!/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"

当您执行上述程序时，它将产生以下结果-

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

运算符优先级

下表列出了从最高优先级到最低优先级的所有运算符。

#!/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

当您执行上述程序时，它将产生以下结果-

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