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📜  Python基本运算符

📅  最后修改于: 2020-12-23 05:12:02             🧑  作者: Mango

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，+称为运算符。

运营商类型

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
  • 按位运算符
  • 会员运营商
  • 身份运算符

让我们一一看一下所有运算符。

Python算术运算符

假设变量a持有10，变量b持有20，则-

[显示示例]

Operator Description Example
+ Addition Adds values on either side of the operator. a + b = 30
– Subtraction Subtracts right hand operand from left hand operand. a – b = -10
* Multiplication Multiplies values on either side of the operator a * b = 200
/ Division Divides left hand operand by right hand operand b / a = 2
% Modulus Divides left hand operand by right hand operand and returns remainder b % a = 0
** Exponent Performs exponential (power) calculation on operators a**b =10 to the power 20
// Floor Division – The division of operands where the result is the quotient in which the digits after the decimal point are removed. But if one of the operands is negative, the result is floored, i.e., rounded away from zero (towards negative infinity) − 9//2 = 4 and 9.0//2.0 = 4.0, -11//3 = -4, -11.0//3 = -4.0

Python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持有10，变量b持有20，则-

[显示示例]

Operator Description Example
== If the values of two operands are equal, then the condition becomes true. (a == b) is not true.
!= If values of two operands are not equal, then condition becomes true. (a != b) is true.
<> If values of two operands are not equal, then condition becomes true. (a <> b) is true. This is similar to != operator.
> If the value of left operand is greater than the value of right operand, then condition becomes true. (a > b) is not true.
< If the value of left operand is less than the value of right operand, then condition becomes true. (a < b) is true.
>= If the value of left operand is greater than or equal to the value of right operand, then condition becomes true. (a >= b) is not true.
<= If the value of left operand is less than or equal to the value of right operand, then condition becomes true. (a <= b) is true.

Python赋值运算符

假设变量a持有10，变量b持有20，则-

[显示示例]

Operator Description Example
= Assigns values from right side operands to left side operand c = a + b assigns value of a + b into c
+= Add AND It adds right operand to the left operand and assign the result to left operand c += a is equivalent to c = c + a
-= Subtract AND It subtracts right operand from the left operand and assign the result to left operand c -= a is equivalent to c = c – a
*= Multiply AND It multiplies right operand with the left operand and assign the result to left operand c *= a is equivalent to c = c * a
/= Divide AND It divides left operand with the right operand and assign the result to left operand c /= a is equivalent to c = c / a
%= Modulus AND It takes modulus using two operands and assign the result to left operand c %= a is equivalent to c = c % a
**= Exponent AND Performs exponential (power) calculation on operators and assign value to the left operand c **= a is equivalent to c = c ** a
//= Floor Division It performs floor division on operators and assign value to the left operand c //= a is equivalent to c = c // a

Python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;和b = 13;现在，以二进制格式，它们的值将分别为0011 1100和0000 1101。下表列出了Python语言支持的按位运算运算符，并分别举例说明，我们将上述两个变量(a和b)用作操作数-

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

[显示示例]

Operator Description Example
& Binary AND Operator copies a bit to the result if it exists in both operands (a & b) (means 0000 1100)
| Binary OR It copies a bit if it exists in either operand. (a | b) = 61 (means 0011 1101)
^ Binary XOR It copies the bit if it is set in one operand but not both. (a ^ b) = 49 (means 0011 0001)
~ Binary Ones Complement It is unary and has the effect of ‘flipping’ bits. (~a ) = -61 (means 1100 0011 in 2’s complement form due to a signed binary number.
<< Binary Left Shift The left operands value is moved left by the number of bits specified by the right operand. a << 2 = 240 (means 1111 0000)
>> Binary Right Shift The left operands value is moved right by the number of bits specified by the right operand. a >> 2 = 15 (means 0000 1111)

Python逻辑运算符

Python语言支持以下逻辑运算符。假设变量a持有10，变量b持有20

[显示示例]

Operator Description Example
and Logical AND If both the operands are true then condition becomes true. (a and b) is true.
or Logical OR If any of the two operands are non-zero then condition becomes true. (a or b) is true.
not Logical NOT Used to reverse the logical state of its operand. Not(a and b) is false.

Python会员运算符

Python的成员资格运算符测试序列中的成员资格，例如字符串，列表或元组。有两个成员运算符，如下所述-

[显示示例]

Operator Description Example
in Evaluates to true if it finds a variable in the specified sequence and false otherwise. x in y, here in results in a 1 if x is a member of sequence y.
not in Evaluates to true if it does not finds a variable in the specified sequence and false otherwise. x not in y, here not in results in a 1 if x is not a member of sequence y.

Python身份运算符

身份运算符比较两个对象的内存位置。下面解释了两个身份运算符-

[显示示例]

Operator Description Example
is Evaluates to true if the variables on either side of the operator point to the same object and false otherwise. x is y, here is results in 1 if id(x) equals id(y).
is not Evaluates to false if the variables on either side of the operator point to the same object and true otherwise. x is not y, here is not results in 1 if id(x) is not equal to id(y).

Python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。

[显示示例]

Sr.No. Operator & Description
1

**

Exponentiation (raise to the power)
2

~ + –

Complement, unary plus and minus (method names for the last two are +@ and -@)
3

* / % //

Multiply, divide, modulo and floor division
4

+ –

Addition and subtraction
5

>> <<

Right and left bitwise shift
6

&

Bitwise ‘AND’
7

^ |

Bitwise exclusive `OR’ and regular `OR’
8

<= < > >=

Comparison operators
9

<> == !=

Equality operators
10

= %= /= //= -= += *= **=

Assignment operators
11

is is not

Identity operators
12

in not in

Membership operators
13

not or and

Logical operators