OPERATORS

An operator is used to perform specific mathematical or logical operation on values are called

operands. For example, in the expression “10 + num”, the value 10, and the variable num are

operands and the + (plus) sign is an operator. Python supports several types of operators as

discussed below.

Arithmetic Operators

Python supports arithmetic operators (+, -, *, /) that are used to perform the four basic arithmetic

operations as well as modulus division (%), floor division (//) and exponentiation (**).

 Addition operator (+) – Adds the two numeric values on either side of the operator. This

operator can also be used to concatenate two strings on either side of the operator.

 Subtraction operator (–) - Subtracts the operand on the right from the operand on the

left.

 Multiplication operator (*) - Multiplies the two values on both side of the operator.

Repeats the item on left of the operator if first operand is a string and second operand is

an integer value.

 Division operator (/) - Divides the operand on the left by the operand on the right and

returns the quotient.

 Modulus operator (%) - Divides the operand on the left by the operand on the right and

returns the remainder.

 Exponent operator (**) - Performs exponential (power) calculation on operands. That is,

raise the operand on the left to the power of the operand on the right.

Relational Operators

Relational operator compares the values of the operands on its either side and determines the

relationship among them.

 Equals to (==) - If the values of two operands are equal, then the condition is

True, otherwise it is False.

 Not equal to (!=) - If values of two operands are not equal, then condition is

True, otherwise it is False.

 Greater than (>) - If the value of the left-side operand is greater than the value of

the right- side operand, then condition is True, otherwise it is False.

 Less than (<) - If the value of the left-side operand is less than the value of the

right- side operand, then condition is True, otherwise it is False operand, then

condition is True, otherwise it is False.

 Greater than or equal to (>=) - If the value of the left-side operand is greater than or

equal to the value of the right-side.

 Less than or equal to (<=) - If the value of the left operand is less than or equal to

the value of the right operand, then is True otherwise it is False.

Assume the Python variables num1 = 10, num2 = 20, num3 = 10, str1 = "Hello", str2 = "Students"

and str3 = ―Hello‖.

Assignment operators.

= Assigns value from right-side operand to left-side operand.

+= It adds the value of right-side operand to the left-side operand and assigns the result

to the left-side operand.

In other words, x += y is same as x = x + y.

-= It subtracts the value of right-side operand from the left-side operand and assigns the

result to left-side operand.

In other words, x-=y is same as x=x-y.

*= It subtracts the value of right-side operand from the left-side operand and assigns the

result to left-side operand.

In other words, x-=y is same as x=x-y.

/= It multiplies the value of right-side operand with the value of left-side operand and

assigns the result to left-side operand.

In other words, x*=y is same as x=x*y.

%= It performs modulus operation using two operands and assigns the results to left -side

operand.

In other words, x % =y is same as x = x % y.

**= It performs exponential (power) calculation on operators and assigns value to the left-

side operand.

In other words, x **= y is same as x = x ** y.

Logical Operators

There are three logical operators ―and, or, not‖ supported by Python. These are to be written in

lower case only. The logical operator evaluates to either True or False based on the logical

operands on either side. Every value is logically either True or False. By default, all values are

True except None, False, 0 (zero), empty collections "", (), [], {}, and few other special values. So, if

we say num1 = 10, num2 = -5, then both num1 and num2 are logically True. If we have num3 =

0, than num3 is logically False.

 Logical AND (and) - If both the conditions are True, then expression becomes True.

 Logical OR (or) - If any of the two condition is True, then expression becomes True.

 Logical NOT (not) - It is used to reverse the logical state of its operand.

The following code as shown in figure 10.19 demonstrates the use of Logical Operators in

Python.

Identity Operators

Identity operators are used to determine whether the value of a variable is of a certain type or not.

Identity operators can also be used to determine whether two variables are referring to the same

object or not.

Membership Operators

Membership operators are used to check if a value is a member of the given sequence or not.

Bitwise Operators

Bitwise operators are the only operators which works on equivalent binary value of the integer

operands. First of all, integer operands are converted into binary then respected operator works

on bit by bit, hence the name is bitwise operators. The result is also converted into decimal

format.