CONDITIONAL STATEMENTS IN PYTHON

Conditional Statements are used to decide whether code has to be execute (or) skip based on the evaluation of the condition. After evaluating the condition, it should return either True or False value.

Elements of conditional statements

In conditional statements we use two elements -

1. Condition - Any expression which returns either True or False value after evaluating that expression is known as "condition"

2. Block - All the statements which are following same space indentation is known as "Block". Block begins with when the indentation increases. Block can contain other blocks. Blocks end when the indentation decreases to zero or to a containing blocks indentation.

Python supports 3 conditional statements. They are -

1. if (or) simple if

Syntax -

if condition : statement

              or

if condition :

        statement1

        statement2

Simple if executes the block if condition returns True. Otherwise, it will skip the execution of the block.

Example 1 -

Name=raw_input('enter name : ')

if Name=='Rakesh':

    print("Hii, Rakesh")

print('Hello, world')

Output 1-

enter name : Rakesh

Hii, Rakesh

Hello, world

Output 2-

enter name : vivek

Hello, world

2. if - else

Syntax -

if condition :

        statement1

        statement2

        ------------

        ------------

else :

        statement1

        -------------

In if-else condition returns True then it will execute if block otherwise it will execute else block.

Example 1 -

Name=raw_input('enter name : ')

if Name=='Rakesh':

    print("Hii, Rakesh")

else :

    print("Hii Stranger")

print('Hello, world')

Output 1 -

enter name : Rakesh

Hii, Rakesh

Hello, world

Output 2 -

enter name : vivek

Hii Stranger

Hello, world

3. elif

Syntax -

if condition :

          statement1

          statement2

          -------------

          -------------

elif condition :

          statement1

          statement2

          ------------

else :

          statement1

          statement2

          ------------

Example 1 -

Name=raw_input('enter name : ')

age=input('enter age : ')

if age<15 :

    print Name,' you are a kid'

elif age<40 :

    print Name,' you are young'

elif age<100 :

    print Name,' you are old'

else :

    print Name,' you are alien'

print 'welcome to codingmakesperfect.blogspot.in'

Output 1 -

enter name : rakesh

enter age : 12

rakesh  you are a kid

welcome to codingmakesperfect.blogspot.in

Output 2 -

enter name : rakesh 

enter age : 26 

rakesh you are young 

welcome to codingmakesperfect.blogspot.in

WRITE A PROGRAM TO FIND BIGGEST NUMBER AMONG 2 NUMBERS

num1=input('enter num1 : ')

num2=input('enter num2 : ')

if num1>num2 :

    print num1,' is big'

else :

    print num2,' is big'

Output 1 -

enter num1 : 15 

enter num2 : 6 

15 is big

Output 2 -

enter num1 : 50 

enter num2 : 70 

70 is big

WRITE A PROGRAM TO FIND BIGGEST NUMBER AMONG 3 NUMBERS

num1=input('enter num1 : ')

num2=input('enter num2 : ')

num3=input('enter num3 : ')

if num1>num2 and num1>num3 :

    print num1,' is big'

elif num2>num3 :

    print num2,' is big'

else :

    print num3,' is big'

Output -

enter num1 : 30 

enter num2 : 20 

enter num3 : 40 

40 is big

WRITE A PROGRAM TO FIND SMALLEST OF 3 NUMBERS

num1=input('enter num1 : ')

num2=input('enter num2 : ')

num3=input('enter num3 : ')

if num1<num2 and num1<num3 :

    print num1,' is small'

elif num2<num3 :

    print num2,' is small'

else :

    print num3,' is small'

Output -

enter num1 : 10 

enter num2 : 20 

enter num3 : 40 

10 is small