Python - Operators



Python Operators

Python operators are special symbols (sometimes called keywords) that are used to perform certain most commonly required operations on one or more operands (value, variables, or expressions).

Types of Operators in Python

Python language supports the following types of operators −

  • Arithmetic Operators

  • Comparison (Relational) Operators

  • Assignment Operators

  • Logical Operators

  • Bitwise Operators

  • Membership Operators

  • Identity Operators

Let us have a look at all the operators one by one.

Python Arithmetic Operators

Arithmetic operators are used to perform basic mathematical operations such as addition, subtraction, multiplication, etc.

Assume variable a holds 10 and variable b holds 20, then

Operator Name Example
+ Addition a + b = 30
- Subtraction a – b = -10
* Multiplication a * b = 200
/ Division b / a = 2
% Modulus b % a = 0
** Exponent a**b =10**20
// Floor Division 9//2 = 4

Example of Python Arithmetic Operators

a = 21
b = 10
c = 0

c = a + b
print ("a: {} b: {} a+b: {}".format(a,b,c))

c = a - b
print ("a: {} b: {} a-b: {}".format(a,b,c) )

c = a * b
print ("a: {} b: {} a*b: {}".format(a,b,c))

c = a / b
print ("a: {} b: {} a/b: {}".format(a,b,c))

c = a % b
print ("a: {} b: {} a%b: {}".format(a,b,c))

a = 2
b = 3
c = a**b 
print ("a: {} b: {} a**b: {}".format(a,b,c))

a = 10
b = 5
c = a//b 
print ("a: {} b: {} a//b: {}".format(a,b,c))

Output

a: 21 b: 10 a+b: 31
a: 21 b: 10 a-b: 11
a: 21 b: 10 a*b: 210
a: 21 b: 10 a/b: 2.1
a: 21 b: 10 a%b: 1
a: 2 b: 3 a**b: 8
a: 10 b: 5 a//b: 2

Python Comparison Operators

Comparison operators compare the values on either side of them and decide the relation among them. They are also called Relational operators.

Assume variable a holds 10 and variable b holds 20, then

Operator Name Example
== Equal (a == b) is not true.
!= Not equal (a != b) is true.
> Greater than (a > b) is not true.
< Less than (a < b) is true.
>= Greater than or equal to (a >= b) is not true.
<= Less than or equal to (a <= b) is true.

Example of Python Comparison Operators

a = 21
b = 10
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 less than b" )
else:
   print ("Line 3 - a is not less than b")

if ( a > b ):
   print ("Line 4 - a is greater than b")
else:
   print ("Line 4 - a is not greater than b")

a,b=b,a #values of a and b swapped. a becomes 10, b becomes 21

if ( a <= b ):
   print ("Line 5 - a is either less than or equal to  b")
else:
   print ("Line 5 - a is neither less than nor equal to  b")

if ( b >= a ):
   print ("Line 6 - b is either greater than  or equal to b")
else:
   print ("Line 6 - b is neither greater than  nor equal to b")

Output

Line 1 - a is not equal to b
Line 2 - a is not equal to b
Line 3 - a is not less than b
Line 4 - a is greater than b
Line 5 - a is either less than or equal to  b
Line 6 - b is either greater than  or equal to b

Python Assignment Operators

Assignment operators are used to assign values to variables. Following is a table which shows all Python assignment operators.

Operator Example Same As
= a = 10 a = 10
+= a += 30 a = a + 30
-= a -= 15 a = a - 15
*= a *= 10 a = a * 10
/= a /= 5 a = a / 5
%= a %= 5 a = a % 5
**= a **= 4 a = a ** 4
//= a //= 5 a = a // 5
&= a &= 5 a = a & 5
|= a |= 5 a = a | 5
^= a ^= 5 a = a ^ 5
>>= a >>= 5 a = a >> 5
<<= a <<= 5 a = a << 5

Example of Python Assignment Operators

a = 21
b = 10
c = 0
print ("a: {} b: {} c : {}".format(a,b,c))
c = a + b
print ("a: {}  c = a + b: {}".format(a,c))

c += a
print ("a: {} c += a: {}".format(a,c))

c *= a
print ("a: {} c *= a: {}".format(a,c))

c /= a 
print ("a: {} c /= a : {}".format(a,c))

c  = 2
print ("a: {} b: {} c : {}".format(a,b,c))
c %= a
print ("a: {} c %= a: {}".format(a,c))

c **= a
print ("a: {} c **= a: {}".format(a,c))

c //= a
print ("a: {} c //= a: {}".format(a,c))

Output

a: 21 b: 10 c : 0
a: 21  c = a + b: 31
a: 21 c += a: 52
a: 21 c *= a: 1092
a: 21 c /= a : 52.0
a: 21 b: 10 c : 2
a: 21 c %= a: 2
a: 21 c **= a: 2097152
a: 21 c //= a: 99864

Python Bitwise Operators

Bitwise operator works on bits and performs bit by bit operation. These operators are used to compare binary numbers.

There are following Bitwise operators supported by Python language

Operator Name Example
& AND a & b
| OR a | b
^ XOR a ^ b
~ NOT ~a
<< Zero fill left shift a << 3
>> Signed right shift a >> 3

Example of Python Bitwise Operators

a = 20            
b = 10            

print ('a=',a,':',bin(a),'b=',b,':',bin(b))
c = 0

c = a & b;        
print ("result of AND is ", c,':',bin(c))

c = a | b;     
print ("result of OR is ", c,':',bin(c))

c = a ^ b;        
print ("result of EXOR is ", c,':',bin(c))

c = ~a;           
print ("result of COMPLEMENT is ", c,':',bin(c))

c = a << 2;       
print ("result of LEFT SHIFT is ", c,':',bin(c))

c = a >> 2;       
print ("result of RIGHT SHIFT is ", c,':',bin(c))

Output

a= 20 : 0b10100 b= 10 : 0b1010
result of AND is  0 : 0b0
result of OR is  30 : 0b11110
result of EXOR is  30 : 0b11110
result of COMPLEMENT is  -21 : -0b10101
result of LEFT SHIFT is  80 : 0b1010000
result of RIGHT SHIFT is  5 : 0b101

Python Logical Operators

Python logical operators are used to combile two or more conditions and check the final result. There are following logical operators supported by Python language. Assume variable a holds 10 and variable b holds 20 then

Operator Name Example
and AND a and b
or OR a or b
not NOT not(a)

Example of Python Logical Operators

var = 5

print(var > 3 and var < 10)
print(var > 3 or var < 4)
print(not (var > 3 and var < 10))

Output

True
True
False

Python Membership Operators

Python's membership operators test for membership in a sequence, such as strings, lists, or tuples. There are two membership operators as explained below −

Operator Description Example
in Returns True if it finds a variable in the specified sequence, false otherwise. a in b
not in returns True if it does not finds a variable in the specified sequence and false otherwise. a not in b

Example of Python Membership Operators

a = 10
b = 20
list = [1, 2, 3, 4, 5 ]

print ("a:", a, "b:", b, "list:", list)

if ( a in list ):
   print ("a is present in the given list")
else:
   print ("a is not present in the given list")

if ( b not in list ):
   print ("b is not present in the given list")
else:
   print ("b is present in the given list")

c=b/a
print ("c:", c, "list:", list)
if ( c in list ):
   print ("c is available in the given list")
else:
    print ("c is not available in the given list")

Output

a: 10 b: 20 list: [1, 2, 3, 4, 5]
a is not present in the given list
b is not present in the given list
c: 2.0 list: [1, 2, 3, 4, 5]
c is available in the given list

Python Identity Operators

Identity operators compare the memory locations of two objects. There are two Identity operators explained below −

Operator Description Example
is Returns True if both variables are the same object and false otherwise. a is b
is not Returns True if both variables are not the same object and false otherwise. a is not b

Example of Python Identity Operators

a = [1, 2, 3, 4, 5]
b = [1, 2, 3, 4, 5]
c = a

print(a is c)
print(a is b)

print(a is not c)
print(a is not b)

Output

True
False
False
True

Python Operators Precedence

The following table lists all operators from highest precedence to lowest.

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

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