> Source URL: /resources/conditionals.guide
# Conditionals

Conditionals let your code make decisions based on whether something is true or false.

## The `if` Statement

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

_Note: the indented code only runs when the condition is `True`._

## `if` / `else`

```python
temperature = 35
if temperature > 90:
    print("It's hot!")
else:
    print("It's not too bad.")
```

## `if` / `elif` / `else`

Use `elif` (short for "else if") to check multiple conditions:

```python
grade = 85
if grade >= 90:
    print("A")
elif grade >= 80:
    print("B")
elif grade >= 70:
    print("C")
else:
    print("Keep trying!")
```

_Tip: Python checks conditions top to bottom and stops at the first match._

## Comparison Operators

| Operator | Meaning                  |
| -------- | ------------------------ |
| `==`     | equal to                 |
| `!=`     | not equal to             |
| `<`      | less than                |
| `>`      | greater than             |
| `<=`     | less than or equal to    |
| `>=`     | greater than or equal to |

```python
name = "Alex"
if name == "Alex":
    print("Hey Alex!")
```

## Logical Operators

Combine conditions with `and`, `or`, and `not`:

```python
age = 16
has_permit = True

if age >= 16 and has_permit:
    print("You can drive!")

if age < 13 or age > 65:
    print("Discount available!")

if not has_permit:
    print("Get a permit first.")
```

## Nested Conditionals

You can put conditionals inside other conditionals:

```python
is_member = True
age = 15

if is_member:
    if age < 18:
        print("Junior member discount!")
    else:
        print("Member discount!")
else:
    print("Sign up for discounts!")
```

## Common Mistakes

**Using `=` instead of `==`**

```python
# Wrong - this assigns, doesn't compare
if score = 100:

# Right - this compares
if score == 100:
```

**Forgetting the colon**

```python
# Wrong
if age > 18
    print("Adult")

# Right
if age > 18:
    print("Adult")
```

**Incorrect indentation**

```python
# Wrong - print is not indented
if age > 18:
print("Adult")

# Right
if age > 18:
    print("Adult")
```


---

## Backlinks

The following sources link to this document:

- [Conditionals Guide](/resources/resources.index.llm.md)
- [>ref: **if/else conditionals**](/unit-1/projects/02-you-dot-py/you-dot-py.project.llm.md)