🕯️ Magic Note
The word elif is unique to Python. Other languages use else if (two words) or elsif or elif (Perl). Python chose elif because it is short, clear, and consistent with the indentation-based syntax. No braces. No end if. Just elif and proper indentation.
Python
temperature = 30
if temperature > 25:
print(“It is a hot day”)
print(“Drink water”)
print(“This runs always”)
Python
age = 16
if age >= 18:
print(“You can vote”)
else:
print(“You are too young to vote”)
🕯️ Magic Note
The else clause catches everything that the if condition does not catch. It is the “otherwise” of your decision. No condition needed after else. Just a colon and an indented block.
Python
score = 85
if score >= 90:
grade = “A”
elif score >= 80:
grade = “B”
elif score >= 70:
grade = “C”
elif score >= 60:
grade = “D”
else:
grade = “F”
print(f”Grade: {grade}”) # Grade: B
Python
age = 25
has_license = True
is_weekend = False
# AND – both must be True
if age >= 18 and has_license:
print(“You can drive”)
# OR – at least one must be True
if is_weekend or age < 12:
print(“Special discount applies”)
# NOT – reverses the condition
if not is_weekend:
print(“It is a weekday”)
# Combining multiple operators
if (age >= 18 and has_license) and not is_weekend:
print(“You can drive to work”)
Python
is_logged_in = True
user_role = “admin”
if is_logged_in:
print(“Welcome back”)
if user_role == “admin”:
print(“You have admin privileges”)
print(“You can delete users”)
else:
print(“You are a regular user”)
else:
print(“Please log in”)
🕯️ Magic Note
Deep nesting (more than 3 levels) makes code hard to read. If you find yourself nesting too deeply, consider using elif chains or extracting logic into functions. Flat is better than nested.
Python
age = 20
# Regular if-else
if age >= 18:
status = “adult”
else:
status = “minor”
# Ternary operator (one line)
status = “adult” if age >= 18 else “minor”
print(status) # adult
# Can be used inside print directly
print(“Eligible” if score >= 60 else “Not eligible”)
Python
# Instead of if len(name) > 0:
name = “Feloriya”
if name:
print(f”Hello {name}”) # This runs (non-empty string is truthy)
# Instead of if len(items) == 0:
items = []
if not items:
print(“The list is empty”) # This runs (empty list is falsy)
# Instead of if count != 0:
count = 5
if count:
print(f”Count is {count}”) # This runs (non-zero is truthy)
Python
# 1. Guard clause (early return)
def divide(a, b):
if b == 0:
return None # Guard against division by zero
return a / b
# 2. Default value assignment
user_input = input(“Enter name: “)
name = user_input if user_input else “Anonymous”
# 3. Range checking with chained comparisons
if 0 <= score <= 100:
print(“Valid score”)
# 4. Member checking
allowed_users = [“Ali”, “Sara”, “Reza”]
if username in allowed_users:
print(“Access granted”)
Python
error_code = 404
if error_code == 200:
pass # TODO: Handle success later
elif error_code == 404:
print(“Page not found”)
else:
pass # TODO: Handle other errors
🕯️ Magic Note
pass does nothing. It is a placeholder that satisfies Python’s need for an indented block. Use it when you are planning to write code later or when you need a block syntactically but not logically.
- Forgetting the colon : after if, elif, or else
- Inconsistent indentation (mixing spaces and tabs)
- Using = instead of == in conditions if x = 5:
- “Forgetting that elif is one word, not “else if”
- Putting else with a condition else x > 5: (else has no condition)
- Deep nesting that makes code unreadable
- Comparing to True or False explicitly if is_ready == True: (just write if is_ready:)
- Write an if-else statement that prints “Positive” for numbers greater than 0 and “Non-positive” otherwise.
- What is wrong with this code: if x = 5: print(“x is 5”)?
- How do you check if a string is empty without using len()?
- Write a ternary operator that assigns “high” if score > 80 else “low”.
- What is the purpose of the pass statement?
- Why does order matter in an if-elif-else chain?
⚡ Whisper
Every decision is a fork in the road. The program stands at the junction, looking left then right. It asks a question. The answer is True or False. Then it moves. This is the breath of logic. This is how code becomes alive. Without if, your program is a straight line to nowhere. With if, it can adapt. It can choose. It can respond to the user, to the data, to the world. elif adds more turns. else catches everything else. Together they form a map of possibilities. Learn to read the map. Learn to draw the forks. Every condition you write is a gift of flexibility to your program.
