---
# System prepended metadata

title: Week 9

---

# Python `if-else` Statements: A Vivid Explanation

Imagine you're a bouncer at an exclusive club. Your job is to decide who gets in based on certain rules. This is exactly how `if-else` statements work in Python - they help your program make decisions.

## The Basic `if` Statement

```python
age = 21

if age >= 18:
    print("You may enter the club!")
```

Think of this like:
- You look at the person's ID (`age = 21`)
- You check your rule: "Is this person 18 or older?" (`age >= 18`)
- If YES, you say "You may enter the club!" (`print()`)
- If NO, you do nothing

## Adding `else`

Now let's give instructions for when the condition isn't met:

```python
age = 16

if age >= 18:
    print("You may enter the club!")
else:
    print("Sorry, you're too young. Come back when you're 18!")
```

This works like:
- Check the age (16)
- Is 16 >= 18? NO
- So we jump to the `else` and say "Sorry..."

## The `elif` (Else If) Ladder

For more complex decisions, we can chain conditions:

```python
temperature = 75

if temperature > 90:
    print("It's scorching! Turn on the AC!")
elif temperature > 70:
    print("Nice warm day!")
elif temperature > 50:
    print("A bit chilly, bring a jacket")
else:
    print("Brrr, it's freezing!")
```

Imagine this as a temperature scanner:
- First checks if it's extremely hot (>90)
- If not, checks if it's pleasantly warm (>70)
- If not, checks if it's moderately cold (>50)
- If none of those, declares it's freezing

## Real-world Example: Movie Ticket Pricing

```python
age = 25
is_student = True

if age < 5:
    print("Free entry!")
elif age <= 12 or is_student:
    print("Child/Student price: $8")
elif age >= 65:
    print("Senior discount: $10")
else:
    print("Regular price: $12")
```

This decision structure:
1. Checks for toddlers (free)
2. Then checks for children or students (discount)
3. Then checks for seniors (discount)
4. Everyone else pays regular price

## Pro Tips:
- Indentation is crucial (use 4 spaces)
- Conditions can be complex (`if x > 5 and y < 10`)
- You can nest `if` statements inside other `if` statements
- `elif` is Python's way of saying "otherwise, check this next condition"

Remember, `if-else` statements are like the branching paths in a choose-your-own-adventure book - they let your program react differently based on different situations!