Day 5: Conditions — Programs That Make Decisions!

What's a Condition?

Think of a traffic light. Green means GO, red means STOP. Your code works the same way — if something is true, do this. If not, do that. That's a condition!

Your First if Statement

age = 21

if age >= 18:
    print("You can vote!")

Is age >= 18? Yes! So "You can vote!" prints. If age was 15, nothing prints. The code decides!

if and else Together

score = 45

if score >= 50:
    print("You passed!")
else:
    print("You failed!")

if runs when TRUE. else runs when FALSE. One or the other — never both!

Multiple Choices with elif

score = 85

if score >= 90:
    print("Grade A!")
elif score >= 70:
    print("Grade B!")
else:
    print("Grade C!")

elif means "else if". Check many conditions in order. First one that's TRUE wins!

Real World Connection

Netflix checks if you're 18+ before showing adult content — that's an if statement! Swiggy checks if your cart total is over 199 for free delivery — if statement! Every decision every app makes is an if/elif/else!

Common Mistakes

Missing the colon — Python will break!

if age >= 18     # WRONG — missing :
if age >= 18:    # CORRECT

Using = instead of == to compare.

if name = "Rohith":   # WRONG — = stores, == compares!
if name == "Rohith":  # CORRECT

Forgetting indentation — code inside if must have spaces!

Mini Challenge

Quick Quiz

Q: What symbol checks if two things are equal? A: == not =!

Q: What runs when the if is FALSE? A: else!

Q: What do you put at the end of every if line? A: A colon :

Key Takeaways