Conditional Statements in Python (if, else, elif) with Examples

Section 01

What is a Conditional Statement?

A conditional statement in Python is used to make decisions in a program. It checks a condition and runs a specific block of code only if that condition is True. If the condition is False, Python skips that block or runs an alternative. Conditional statements make programs smart and responsive to inputs.

How Conditional Logic Works

Start

→

Check Condition

✅ True → Run Block

❌ False → Skip

End

💡 Key Idea: Conditional statements are Python's way of making decisions — just like humans decide based on a situation.

Section 02

if Statement

The if statement is the most basic conditional statement. It checks a condition — if True, the code block inside runs. If False, Python skips it completely. The if statement uses a colon : at the end and the code inside must be indented (4 spaces). Indentation is mandatory in Python — missing it causes an IndentationError. The if statement checks only one condition at a time and runs the block only once when the condition is met.

📋 Syntax:

if condition: # runs only if True statement

💻 Example 1 — Age Check:

Python

age = 20

if age >= 18:

    print("You are an adult.")

👆 Output:

You are an adult.

💻 Example 2 — False condition:

Python

marks = 40

if marks >= 50:

    print("Passed!")

# marks = 40, NOT >= 50 → nothing printed

👆 Output:

(no output — condition was False)

📝 Important Notes:

•Condition must be followed by colon :

•Code inside must be indented (4 spaces)

•If False, the block is completely skipped

•Multiple lines can be written inside one if block

Section 03

if-else Statement

The if-else adds an alternative path when the condition is False. When if is True, the if block runs. When False, the else block runs instead. One of the two blocks always executes — never both, never neither. This makes if-else perfect for binary decisions like pass/fail, yes/no, or login/deny. The else keyword takes no condition — it handles all False cases automatically from the if above it.

📋 Syntax:

if condition: statement_1 # True → runs this else: statement_2 # False → runs this

💻 Example 1 — Pass or Fail:

Python

marks = 75

if marks >= 50:

    print("Passed!")

else:

    print("Failed!")

👆 Output:

Passed!

💻 Example 2 — Even or Odd:

Python

num = 7

if num % 2 == 0:

    print(num, "is Even")

else:

    print(num, "is Odd")

👆 Output:

7 is Odd

📝 Important Notes:

•else never takes a condition

•Exactly ONE block runs — if OR else, never both

•else must be aligned with its matching if

•Best for all binary (two-option) decisions

Section 04

if-elif-else Statement

The elif (else if) is used to check multiple conditions one by one. Python checks the first if — if True it runs that block and skips the rest. If False, it checks the next elif. This continues until a True condition is found. If none match, the final else runs. You can use as many elif blocks as needed. This is the standard way to handle multiple choices like grades, menus, or categories in Python programs.

📋 Syntax:

if condition_1: statement_1 elif condition_2: statement_2 elif condition_3: statement_3 else: statement_4 # none matched

💻 Example — Grade System:

Python

marks = 72

if marks >= 90:

    print("Grade: A+")

elif marks >= 80:

    print("Grade: A")

elif marks >= 70:

    print("Grade: B")

elif marks >= 60:

    print("Grade: C")

else:

    print("Grade: F")

👆 Output:

Grade: B

📝 Important Notes:

•Checks conditions top to bottom — stops at first True

•You can use as many elif blocks as needed

•Only one block ever runs — the first matching one

•Final else is optional but always recommended

Section 05

Nested if Statement

A nested if is an if statement written inside another if. It checks a second condition only after the first condition is already True. The outer if runs first — if True, Python enters and then checks the inner if. This is useful for multi-level decisions like checking age first then gender, or verifying username then password. Proper indentation is critical — each inner level must be indented further to the right.

📋 Syntax:

if outer_condition: if inner_condition: inner_block else: inner_else else: outer_else

💻 Example — Voter Check:

Python

age    = 20

has_id = True

if age >= 18:

    print("Age OK.")

    if has_id:

        print("You can vote!")

    else:

        print("No ID. Cannot vote.")

else:

    print("Too young to vote.")

👆 Output:

Age OK.
You can vote!

📝 Important Notes:

•Inner if runs only when outer if is True

•Each nested level needs more indentation

•Avoid too many levels — code becomes unreadable

•Use and operator instead of nested if for simple cases

Section 06

Short if (One-line / Ternary)

The short if — also called the ternary operator — lets you write a complete if-else in just one single line. It is used when the condition and result are simple. The syntax puts the true value first, then the condition with if, then the false value with else. It is not suitable for complex logic but is very useful for quick assignments. It makes code compact, clean, and easy to read for simple decisions.

📋 Syntax:

value = true_val if condition else false_val

💻 Example 1 — Adult or Minor:

Python

age    = 20

status = "Adult" if age >= 18 else "Minor"

print(status)

👆 Output:

Adult

💻 Example 2 — Max number:

Python

a   = 15

b   = 22

big = a if a > b else b

print("Bigger:", big)

👆 Output:

Bigger: 22

💻 Example 3 — Even or Odd in print:

Python

num = 8

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

👆 Output:

Even

📝 Important Notes:

•Order: true_value → if condition → else → false_value

•Perfect for simple one-condition assignments

•Can be used directly inside print()

•Do NOT use for complex multi-statement logic

Section 07

📌 Important Notes

These are the most important rules you must always remember when using conditional statements in Python.

📝 Rule 1 — Indentation is Mandatory

Python

# ✅ Correct

if True:

    print("OK!")

# ❌ Wrong — causes IndentationError

# if True:

# print("Error!")

📝 Rule 2 — Colon is Required

Python

# ✅ Correct

if x > 5:           # ← colon needed!

    print("Yes")

# ❌ Wrong — SyntaxError

# if x > 5

# print("Yes")

📝 Rule 3 — Truthy and Falsy Values

Python

# Falsy: 0, "", [], {}, None, False

if 0:

    print("runs")     # ← never runs

if 1:

    print("runs!")    # ← always runs

•Always use == to compare, NOT = (assignment)

•Python checks conditions top to bottom — first True wins

•Avoid deeply nested ifs — use and/or to simplify

•else and elif blocks are always optional

•You can compare strings: if name == "Ali":

Section 08

🌍 Real-Life Examples

Here are real-world scenarios showing how conditional statements are used in actual Python programs.

🏧 1. ATM Withdrawal

Python

balance  = 5000

withdraw = 3000

if withdraw <= balance:

    balance -= withdraw

    print("Withdrawn!")

    print("Balance:", balance)

else:

    print("Insufficient balance!")

👆 Output:

Withdrawn!
Balance: 2000

🔐 2. Login System

Python

username = "admin"

password = "1234"

if username == "admin" and password == "1234":

    print("Login successful!")

else:

    print("Wrong credentials.")

👆 Output:

🌡️ 3. Temperature Checker

Python

temp = 38

if temp >= 40:

    print("Very Hot!")

elif temp >= 30:

    print("Hot day.")

elif temp >= 20:

    print("Pleasant.")

else:

    print("Cold day.")

👆 Output:

Hot day.

🛒 4. Shopping Discount

Python

total = 1500

if total >= 2000:

    discount = 20

elif total >= 1000:

    discount = 10

else:

    discount = 0

print(f"Discount: {discount}%")

pay = total - (total * discount // 100)

print(f"Pay: {pay}")

👆 Output:

Discount: 10%
Pay: 1350

🌟 Key Takeaway: Conditional statements are in every real program — banking, login systems, shopping apps, and games. Mastering them is the most important step in Python!

Summary

📋 All Conditional Statements

▶if — runs block only when condition is True

▶if-else — if True → if block, if False → else block

▶if-elif-else — checks multiple conditions one by one

▶Nested if — if inside another if (multi-level check)

▶Short if — complete if-else in one single line

💡 Always remember:
✅ Every if/elif needs a colon :
✅ Code inside must be indented
✅ Use == to compare, not =
✅ Only the first True condition ever runs

Python Conditional if-else Beginner