Python If Else Statement - Syntax, Examples
Python If-Else Statement
Python If Else statement is used to implement conditional execution where in if the condition evaluates to True, if-block statement(s) are executed or if the condition evaluates to False, else-block statement(s) are executed.
Python If-Else is an extension of Python If statement where we have an else block that executes when the condition is False
.
Syntax of If-Else
The syntax of Python if-else statement is given below.
if boolean_expression:
statement(s)
else:
statement(s)
Observe the indentation for the lines after if keyword and else keyword. if and else are in a line of indentation while the statements inside if block and else block are in next possible indentation.
Examples
1. If Else with condition True
In the following example, we have a condition that will evaluate to true and the statement(s) of if block are executed.
Python Program
a = 2
b = 4
if a<b:
print(a, 'is less than', b)
else:
print(a, 'is not less than', b)
Output
2 is less than 4
2<4
returns True, and hence the if block is executed.
2. If Else with condition False
In the following if-else statement, we have a condition that will evaluate to false and the statement(s) of else block are executed.
Python Program
a = 5
b = 4
if a<b:
print(a, 'is less than', b)
else:
print(a, 'is not less than', b)
Output
5 is not less than 4
5<4
returns False, and hence the else block is executed.
3. Nested If Else
You can have nested if-else statements, i.e., if-else statement inside an if-else statement. After all, if-else is just another Python statement.
Python Program
a = 2
b = 4
c = 5
if a<b:
print(a, 'is less than', b)
if c<b:
print(c, 'is less than', b)
else:
print(c, 'is not less than', b)
else:
print(a, 'is not less than', b)
Output
2 is less than 4
5 is not less than 4
Thus using nested if-else statements, you could implement a complex business login in your Python application.
Summary
In this tutorial of Python Examples, we learned what an if-else statement does in Python, how to write an if-else statement, and scenarios like nested if-else statements, all with the help of well detailed examples.