Python (Page-2)

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 DATA TYPES and Introduction to Operators

Data types tell about the type of data hold by a variable and the type of operations that can be performed on that particular variable. 

Taken From NCERT

Examples-

• int data type stores integer numbers like 4, 5 , -3, 0  etc. 
• float data type stores the floating point numbers like -3.4, 6.7, etc. 
• list variable holds a number of data items enclosed in [] like        city_list=["delhi", "nagpur","Hydrabad"]

Operators

Operators are used to perform specific mathematical or logical operations on values. Operands are the the data items on which operators are applied. 

For Example- A+B, Here A and B are called operand and + is an Operator. 

In Python, we have a variety of operators. 

1. Arithmetic Operators
2. Relational Operators
3. Assignment Operators
4. Logical Operators
5. Identity Operators
6. Membership Operators

(1) Arithmetic Operators

Arithmetic Operators
Operator	Operation	Description	Example
+	Addition	It adds two numbers or concatenates the strings	1+1=2 “hello”+”class”=”helloclass”
-	Subtraction	It subtracts the two numbers	2-1=1
*	Multiplication	It Multiplies the two numbers or Repeats a String	2*3=6 “Hello”*2= HelloHello
/	Division	It divides the two numbers	6/2=3.0
%	Modulus	Used to get the remainder	14%3=2(remainder)
//	Floor Division	Gives the quotient by removing the decimal part	14//3=3.0
**	Exponent	Used to calculate “Power of operation” or exponent	3**2=9

(2) Relational Operators

Relational Operators
Operator	Operation	Description	Example
==	Equals to	Compares two values if they are equal	1==1 returns True 2==1 returns False
!=	Not Equals to	Compares two values if they are not equal	1!=1 returns False 2!=1 returns True
>	Greater Than	Compare if the value on the left side is greater than	2>1 returns True 1>2 returns False
<	Less Than	Compare if the value on the left side is less than	2<1 Returns False 1<2 Returns True
>=	Greater Than or Equal to	Compare if the value on the left side is greater than or Equal to	2>=1 returns True 1>=1 returns True
<=	Less Than or Equal to	Compare if the value on the left side is less than or Equal to	2<=1 Returns False 1<=1 Returns True

(3) Assignment Operators

Assignment Operators
Operator	Description	Example
=	Assigns Value	x=2 x variable is assigned value 2
+=	Adds and Assigns x+=y Same as x=x+y	x=2 y=3 x+=y makes the x=5
-=	Subtracts and Assign x -= y is same as x = x - y	x=5 y=3 x-=y makes the x=2
*=	Multiply and Assign x *= y is same as x = x * y	x=5 y=3 x*=y makes the x=15
/=	Divides and Assign x /= y is same as x = x / y	x=15 y=3 x/=y makes the x=5.0
%=	Modulus and Assign x %= y is same as x = x % y	x=5 y=3 x%=y makes the x=2
//=	Floor Division and Assign x //= y is same as x = x // y	x=5 y=3 x//=y makes the x=1.0
**=	Exponent and assign x **= y is same as x = x ** y	x=3 y=2 x**=y makes the x=9

NOTE- Any Non-Zero value is considered as True in python. 

(4) Logical Operators

Logical Operators
Operator	Description	Example
and	Logical AND	>>>1 and 0 Results in False
or	Logical OR	>>>1 or 0 Results in True
not	Logical NOT	>>> not 1 Results in False

Precedence of Operators

Operators are evaluated according to their precedence like we did in our maths class where we solve a given mathematical expression according to the BODMAS Rule. 

Example-

What will be the answer of 2*3+4?

Here, we need to understand whether we should do the 2*3 first or 3+4 first. 

Now, because * operator has higher precedence than that of +, we will do 2*3 first, and than 6 will be added to 4. Accordingly, the answer will be 10.

Precedence determines which operator should be evaluated first. 

Order of Precedence of different Operators in decreasing order-

 

1        ** Exponentiation (raise to the power)

2         ~ ,+, - Complement, unary plus, and unary minus

3         * ,/, %, // Multiply, divide, modulo and floor division

4         +, - Addition and subtraction

5         <= , < , > , >=, == , != Relational and Comparison operators

6          =, %=, /=, //=, -=, +=, *=, **= Assignment operators

7          is, is not Identity operators

8          in, not in Membership operators

9          not

10        and Logical operators

11        or

Note- 

1)if Parenthesis () is used in an expression, it will be evaluated first. 

2) if operators with the same precedence are used in an expression, it will be evaluated from left or right. 

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