> ## Documentation Index
> Fetch the complete documentation index at: https://python4ai.codewithsiva.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# If statements

> Make decisions in your code

## What are if statements?

If statements let your program make decisions. They check if something is true or false, then act accordingly.

Real-life logic:

* IF it's raining THEN take umbrella
* IF battery \< 20% THEN charge phone
* IF password correct THEN allow access

## Basic if statement

```python theme={null}
age = 18

if age >= 18:
    print("You can vote!")
    print("You're an adult")
```

How it works:

1. Check the condition (`age >= 18`)
2. If True, run the indented code
3. If False, skip it

<Note>
  The colon `:` and indentation are required! This is how Python knows what code belongs to the if statement.
</Note>

## If-else statements

Handle both True and False cases:

```python theme={null}
temperature = 25

if temperature > 30:
    print("It's hot!")
else:
    print("Nice weather!")
```

## If-elif-else chains

For multiple conditions:

```python theme={null}
score = 85

if score >= 90:
    print("A - Excellent!")
elif score >= 80:
    print("B - Good job!")
elif score >= 70:
    print("C - Keep it up!")
else:
    print("F - Need improvement")
```

Python checks each condition in order and runs the first True one.

<Note>
  Why `elif` instead of multiple `if` statements? With `elif`, Python stops checking once it finds a true condition. This is more efficient and prevents multiple blocks from running. The order matters - always put more specific conditions first!
</Note>

## Multiple conditions

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

```python theme={null}
age = 25
has_license = True

# Both must be True
if age >= 18 and has_license:
    print("You can drive!")

# At least one must be True
if weekend or holiday:
    print("No work today!")

# Reverse the condition
if not raining:
    print("Let's go outside!")
```

## Nested if statements

Put if statements inside other if statements:

```python theme={null}
has_ticket = True
age = 15

if has_ticket:
    if age >= 18:
        print("Enjoy the movie!")
    else:
        print("Need adult supervision")
else:
    print("Buy a ticket first")
```

## Common mistakes

<AccordionGroup>
  <Accordion title="Forgetting the colon">
    ```python theme={null}
    # Wrong
    if x > 5
        print("Big")

    # Right
    if x > 5:
        print("Big")
    ```
  </Accordion>

  <Accordion title="Using = instead of ==">
    ```python theme={null}
    # Wrong (assignment)
    if x = 5:
        print("Five")

    # Right (comparison)
    if x == 5:
        print("Five")
    ```
  </Accordion>

  <Accordion title="Wrong indentation">
    ```python theme={null}
    # Wrong
    if True:
    print("Hello")  # IndentationError

    # Right
    if True:
        print("Hello")
    ```
  </Accordion>
</AccordionGroup>

## What's next?

Now let's learn about loops to repeat code efficiently!

<Card title="Loops" icon="rotate" href="/basics/loops">
  Repeat code without copying
</Card>