Conditional Statements in Python

Introduction

In real life, we make decisions every day:

If it rains, take an umbrella.
If you pass the exam, you get a certificate.

Similarly, in Python, conditional statements are used to make decisions and execute different blocks of code based on conditions.

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Definition

Conditional statements in Python allow a program to execute specific code only when a given condition is true. If the condition is false, another block of code can be executed.

Python uses the following conditional statements:

if
if-else
if-elif-else
nested if

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Syntax / Structure

Basic if Syntax


if condition:
    statement(s)

if-else Syntax


if condition:
    statement(s)
else:
    statement(s)

if-elif-else Syntax


if condition1:
    statement(s)
elif condition2:
    statement(s)
else:
    statement(s)

Important:

Python uses indentation (spaces) instead of brackets { }.
Indentation defines the code block.

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Types of Conditional Statements in Python

if Statement – Executes code only if the condition is true.
if-else Statement – Executes one block if true, another if false.
if-elif-else Statement – Used to check multiple conditions.
Nested if Statement – An if statement inside another if.

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Examples

Example 1: if Statement


age = 18

if age >= 18:
    print("You are eligible to vote")

Example 2: if-else Statement


num = 5

if num % 2 == 0:
    print("Even number")
else:
    print("Odd number")

Example 3: if-elif-else Statement


marks = 85

if marks >= 90:
    print("Grade A")
elif marks >= 75:
    print("Grade B")
elif marks >= 50:
    print("Grade C")
else:
    print("Fail")

Example 4: Nested if Statement


username = "admin"
password = "1234"

if username == "admin":
    if password == "1234":
        print("Login successful")
    else:
        print("Wrong password")
else:
    print("Wrong username")

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