Operators
Operators are the constructs, which can manipulate the value of operands. Consider the expression 4 + 5 = 9. Here, 4 and 5 are called operands and + is called the operator.
Types of Operator
Python language supports the following types of operators-
- Arithmetic Operators
- Comparison (Relational) Operators
- Assignment Operators
- Logical Operators
- Bitwise Operators
- Membership Operators
- Identity Operators
Python Arithmetic Operators
Assume variable a holds the value 10 and variable b holds the value 21, then-
Operators and their description:-
-
+ Addition
Adds values on either side of the operator.
example:-
a + b = 31
-
- Subtraction
Subtracts right hand operand from left hand operand.
example:-
a - b = -11
-
* Multiplication
Multiplies values on either side of the operator
example:-
a * b = 210
-
/ Division
Divides left hand operand by right hand operand
example:-
b / a = 2.1
-
% Modulus
Divides left hand operand by right hand operand and returns remainder
example:-
b%a=1
-
** Exponent
Performs exponential (power) calculation on operators
example:-
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.
example:-
9//2 = 4 and 9.0//2.0 = 4.0
Python Comparison Operators
These 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 the value 10 and variable b holds the value 20, then-
-
==
If the values of two operands are equal, then the condition becomes true.
example:-
(a == b) is not true.
-
!=
If values of two operands are not equal, then condition becomes true.
example:-
(a!= b) is true.
-
>
If the value of left operand is greater than the value of right operand, then condition becomes true.
example:-
(a > b) is not true.
-
<
If the value of left operand is less than the value of right operand, then condition becomes true.
example:-
(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.
example:-
(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.
example:-
(a <= b) is true.
Python Assignment Operators
Assume variable a holds 10 and variable b holds 20, then-
-
=
Assigns values from right side operands to left side operand
example:-
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
example:-
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
example:-
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
example:-
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
example:-
c /= a is equivalent to c = c / ac /= a is equivalent to c = c / a
-
%= Modulus AND
It takes modulus using two operands and assign the result to left operand
example:-
c %= a is equivalent to c = c % a
-
**= Exponent AND
Performs exponential (power) calculation on operators and assign value to the left operand
example:-
c **= a is equivalent to c = c ** a
-
//= Floor Division
It performs floor division on operators and assign value to the left operand
example:-
c //= a is equivalent to c = c // a
Python Bitwise Operators
Bitwise operator works on bits and performs bit-by-bit operation. Assume if a = 60; and b = 13; Now in binary format they will be as follows-
a = 0011 1100
b = 0000 1101
-----------------
a&b = 0000 1100
a|b = 0011 1101
a^b = 0011 0001
~a = 1100 0011
Pyhton's built-in function bin() can be used to obtain binary representation of an integer number.
The following Bitwise operators are supported by Python language-
-
& Binary AND
Operator copies a bit to the result, if it exists in both operands
example:-
(a & b) (means 0000 1100)
-
| Binary OR
It copies a bit, if it exists in either operand.
example:-
-
^ Binary XOR
It copies the bit, if it is set in one operand but not both.
example:-
(a ^ b) = 49 (means 0011 0001)
-
~ Binary Ones Complement
It is unary and has the effect of 'flipping' bits.
example:-
(~a ) = -61 (means 1100 0011 in 2's complement form due to a signed binary number.
-
<< Binary Left Shift
The left operand’s value is moved left by the number of bits specified by the right operand.
example:-
a << = 240 (means 1111 0000)
-
>> Binary Right Shift
The left operand’s value is moved right by the number of bits specified by the right operand.
example:-
a >> = 15 (means 0000 1111)
Python Logical Operators
The following logical operators are supported by Python language. Assume variable a holds True and variable b holds False then-
-
and Logical AND
If both the operands are true then condition becomes true.
example:-
(a and b) is False.
-
or Logical OR
If any of the two operands are non-zero then condition becomes true.
example:-
(a or b) is True.
-
not Logical NOT
Used to reverse the logical state of its operand.
example:-
Not(a and b) is True.
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-
-
in
Evaluates to true, if it finds a variable in the specified sequence and false otherwise.
example:-
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 find a variable in the specified sequence and false otherwise.
example:-
x not in y, here not in results in a 1 if x is not a member of sequence Y
Python Identity Operators
Identity operators compare the memory locations of two objects. There are two Identity operators as explained below:
-
is
Evaluates to true if the variables on either side of the operator point to the same object and false otherwise.
example:-
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.
example:-
x is not y, here is not results in 1 if id(x) is not equal to id(y)
Python Operators Precedence
The following table lists all the operators from highest precedence to the lowest.
-
**
Exponentiation (raise to the power)
-
~ +-
Ccomplement, unary plus and minus (method names for the last two are +@ and -@)
-
* / % //
Multiply, divide, modulo and floor division
-
+-
Addition and subtraction
-
>> <<
Right and left bitwise shift
-
&
Bitwise 'AND'
-
^|
Bitwise exclusive `OR' and regular `OR'
-
<= < > >=
Comparison operators
-
<> == !=
Equality operators
-
= %= /= //= -= += *= **=
Assignment operators
-
is is not
Identity operators
-
in not in
Membership operators
-
not or and
Logical operators
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