Python运算符

Python运算符通常用于对值和变量执行操作。这些是用于逻辑和算术运算的标准符号。在本文中，我们将研究不同类型的Python运算符。

算术运算符

算术运算运算符用于执行数学运算，例如加法、减法、乘法和除法。

Operator	Description	Syntax
+	Addition: adds two operands	x + y
–	Subtraction: subtracts two operands	x – y
*	Multiplication: multiplies two operands	x * y
/	Division (float): divides the first operand by the second	x / y
//	Division (floor): divides the first operand by the second	x // y
%	Modulus: returns the remainder when the first operand is divided by the second	x % y
**	Power: Returns first raised to power second	x ** y

示例： Python中的算术运算符

Python3

# Examples of Arithmetic Operator
a = 9
b = 4
 
# Addition of numbers
add = a + b
 
# Subtraction of numbers
sub = a - b
 
# Multiplication of number
mul = a * b
 
# Division(float) of number
div1 = a / b
 
# Division(floor) of number
div2 = a // b
 
# Modulo of both number
mod = a % b
 
# Power
p = a ** b
 
# print results
print(add)
print(sub)
print(mul)
print(div1)
print(div2)
print(mod)
print(p)

输出

13
5
36
2.25
2
1
6561

注意：有关这两个运算符的一些有趣事实，请参阅 / 和 // 之间的差异。

比较运算符

关系运算符的比较比较值。它根据条件返回True或False 。

Operator	Description	Syntax
>	Greater than: True if the left operand is greater than the right	x > y
<	Less than: True if the left operand is less than the right	x < y
==	Equal to: True if both operands are equal	x == y
!=	Not equal to – True if operands are not equal	x != y
>=	Greater than or equal to True if the left operand is greater than or equal to the right	x >= y
<=	Less than or equal to True if the left operand is less than or equal to the right	x <= y

示例： Python中的比较运算符

Python3

# Examples of Relational Operators
a = 13
b = 33
 
# a > b is False
print(a > b)
 
# a < b is True
print(a < b)
 
# a == b is False
print(a == b)
 
# a != b is True
print(a != b)
 
# a >= b is False
print(a >= b)
 
# a <= b is True
print(a <= b)

输出

False
True
False
True
False
True

逻辑运算符

逻辑运算符执行逻辑与、逻辑或和逻辑非运算。它用于组合条件语句。

Operator	Description	Syntax
and	Logical AND: True if both the operands are true	x and y
or	Logical OR: True if either of the operands is true	x or y
not	Logical NOT: True if the operand is false	not x

示例： Python中的逻辑运算符

Python3

# Examples of Logical Operator
a = True
b = False
 
# Print a and b is False
print(a and b)
 
# Print a or b is True
print(a or b)
 
# Print not a is False
print(not a)

输出

False
True
False

位运算符

位运算符作用于位并执行逐位操作。这些用于对二进制数进行操作。

Operator	Description	Syntax
&	Bitwise AND	x & y
|	Bitwise OR	x | y
~	Bitwise NOT	~x
^	Bitwise XOR	x ^ y
>>	Bitwise right shift	x>>
<<	Bitwise left shift	x<<

示例： Python中的位运算符

Python3

# Examples of Bitwise operators
a = 10
b = 4
 
# Print bitwise AND operation
print(a & b)
 
# Print bitwise OR operation
print(a | b)
 
# Print bitwise NOT operation
print(~a)
 
# print bitwise XOR operation
print(a ^ b)
 
# print bitwise right shift operation
print(a >> 2)
 
# print bitwise left shift operation
print(a << 2)

输出

0
14
-11
14
2
40

赋值运算符

赋值运算符用于为变量赋值。

Operator	Description	Syntax
=	Assign value of right side of expression to left side operand	x = y + z
+=	Add AND: Add right-side operand with left side operand and then assign to left operand	a+=b     a=a+b
-=	Subtract AND: Subtract right operand from left operand and then assign to left operand	a-=b     a=a-b
*=	Multiply AND: Multiply right operand with left operand and then assign to left operand	a*=b     a=a*b
/=	Divide AND: Divide left operand with right operand and then assign to left operand	a/=b     a=a/b
%=	Modulus AND: Takes modulus using left and right operands and assign the result to left operand	a%=b     a=a%b
//=	Divide(floor) AND: Divide left operand with right operand and then assign the value(floor) to left operand	a//=b     a=a//b
**=	Exponent AND: Calculate exponent(raise power) value using operands and assign value to left operand	a**=b     a=a**b
&=	Performs Bitwise AND on operands and assign value to left operand	a&=b     a=a&b
|=	Performs Bitwise OR on operands and assign value to left operand	a|=b     a=a|b
^=	Performs Bitwise xOR on operands and assign value to left operand	a^=b     a=a^b
>>=	Performs Bitwise right shift on operands and assign value to left operand	a>>=b     a=a>>b
<<=	Performs Bitwise left shift on operands and assign value to left operand	a <<= b     a= a << b

示例： Python中的赋值运算符

Python3

# Examples of Assignment Operators
a = 10
 
# Assign value
b = a
print(b)
 
# Add and assign value
b += a
print(b)
 
# Subtract and assign value
b -= a
print(b)
 
# multiply and assign
b *= a
print(b)
 
# bitwise lishift operator
b <<= a
print(b)

输出

10
20
10
100
102400

身份运算符

is和is not是身份运算符，两者都用于检查两个值是否位于内存的同一部分。两个相等的变量并不意味着它们是相同的。

is          True if the operands are identical 
is not      True if the operands are not identical 

示例：身份运算符

Python3

a = 10
b = 20
c = a
 
print(a is not b)
print(a is c)

输出

True
True

会员运营商

in和not in是成员运算符；用于测试一个值或变量是否在一个序列中。

in            True if value is found in the sequence
not in        True if value is not found in the sequence

示例：成员运算符

Python3

# Python program to illustrate
# not 'in' operator
x = 24
y = 20
list = [10, 20, 30, 40, 50]
 
if (x not in list):
    print("x is NOT present in given list")
else:
    print("x is present in given list")
 
if (y in list):
    print("y is present in given list")
else:
    print("y is NOT present in given list")

输出

x is NOT present in given list
y is present in given list

运算符的优先级和关联性

运算符的优先级和关联性：运算符的优先级和关联性决定了运算符符的优先级。

运算符优先级

这用于具有多个具有不同优先级的运算符的表达式中，以确定首先执行哪个操作。

示例：运算符优先级

Python3

# Examples of Operator Precedence
 
# Precedence of '+' & '*'
expr = 10 + 20 * 30
print(expr)
 
# Precedence of 'or' & 'and'
name = "Alex"
age = 0
 
if name == "Alex" or name == "John" and age >= 2:
    print("Hello! Welcome.")
else:
    print("Good Bye!!")

输出

610
Hello! Welcome.

运算符关联性

如果一个表达式包含两个或多个具有相同优先级的运算符符，则使用运算符关联性来确定。它可以是从左到右或从右到左。

示例：运算符关联性

Python3

# Examples of Operator Associativity
 
# Left-right associativity
# 100 / 10 * 10 is calculated as
# (100 / 10) * 10 and not
# as 100 / (10 * 10)
print(100 / 10 * 10)
 
# Left-right associativity
# 5 - 2 + 3 is calculated as
# (5 - 2) + 3 and not
# as 5 - (2 + 3)
print(5 - 2 + 3)
 
# left-right associativity
print(5 - (2 + 3))
 
# right-left associativity
# 2 ** 3 ** 2 is calculated as
# 2 ** (3 ** 2) and not
# as (2 ** 3) ** 2
print(2 ** 3 ** 2)

输出

100.0
6
0
512

Python运算符测验