Python Decision making

 4) Decision making

Evaluates expression with outcome as True or False.

4.1 Block Structure and Whitespace

code executed when a specific condition met is defined in a "block."

block structure in python is done by indentation.

use 4 spaces(1TAB) for each level of block indentation.

If Statement:

#!/usr/bin/python

var1 = 10

if var1:

   print ("Got desired value")

   print (var1)

IF Else Statement:

var = 0

if var:

   print ("Got true expression value")

   print (var)

else:

   print ("Got false expression value")

   print (var)

O/p:

Got false expression value

0

elif statement:

if expression1:

   statement(s)

elif expression2:

   statement(s)

elif expression3:

   statement(s)

else:

   statement(s)

if elseif:

if expression1:

   statement(s)

   if expression2:

      statement(s)

   elif expression3:

      statement(s)

   elif:

      statement(s)

   elif expression4:

      statement(s)

else:

   statement(s)

Nested loops:

n = int(input('enter number :'))

if n % 2 != 0:

    print('Odd number')

elif n % 2 == 0:

    if (n >= 2 and n <= 99):

        print('Two digit even number')

    elif (n >= 100 and n <= 999):

        print ('3 digit even number')

    else:

        print('>= 4 digit  even number ')

else:

    print('done')