Python If, Else and Elif Statements with Example

In this article, we will going to learn about decision making statement of python programming language. 

In some situations the programmers have to make decisions and the next block of code will we executed based on these decisions. Here in python, the if...else...elif and nested if statement is used as the decision making statement.

Python if statement

This is the most simplest decision making statement of python programming language. This statement is used when the programmer has to decide whether to execute a certain block of code or not. It means that if a conditions is true then the block of code will be executed and if it is false then it will not be executed. In python, the non zero values are interpreted as true and the 0 and None are interpreted as False.

Syntax

if expression:
  statements

Flow Chart of Python if statement

Python if statement Example ;

a = 10
b = 5
if a > b :
  print(" A is greater term ")

Output

A is greater term

Python if...else statement

If...else statement is used by the programmers to execute a block of code in a situation where the condition is false. The if...else statement is used to evaluate the test expression and if the condition is to then the block of code will be executed but if the condition is false, then the body of else will be executed.

Syntax

if expression:
   statements 
else:
   statements

Flow Chart of python if...else statement

Python if...else statement Example;

a = 5
b = 10
if a > b :
  print(" A is greater term ")
else :
  print(" B is greater term ")

Output

B is greater term

Python if...elif...else statement

In python, if...elif...else statement is used when the programmer have to multiple expressions. When the condition of if is false then the next elif block is checked and if it is also false then next block is checked and so on. And if all the conditions comes out as false then the body of else will be executed. Here, in if block we can have multiple elif block but only one else block.

Syntax

if expression:
  statements
elif expression:
  statements
else:
  statements

Flow Chart of python if...elif...else statement

Python if...elif...else statement Example;

a = 200
if a > 100 :
  print(" A is greater than 100 ")
elif a < 100 :
  print(" A is less than 100 ")
elif a == 100 :
  print(" A is 100 ")
else :
  print(" A is not a number ")

Output

A is greater than 100

Python Nested if statement 

When we writes a if...elif...else statement is written inside the other if...elif...else statement then it is known as nested if statement. Simply, we can say that in python, we can easily place a statement inside the other statement.

Syntax

if condition:
  if condition:
    statements
  else:
    statements
else:
  statements

Flow chart of python Nested if statement

Python Nested if statement Example;

x = 5
if (x == 5):
    if (x < 10):
        print("The x is smaller than 10")
    if (x < 7):
        print("The x is smaller than 7 too")
    else:
        print("The x is greater than 10")

Output

The x is smaller than 10


The x is smaller than 7 too

Conclusion

Above we have discussed about decision making statement of python programming language. In some situations the programmers have to make decisions and the next block of code will we executed based on these decisions. In python, the if...else...elif and nested if statement is used as the decision making statement.