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

# Python Error Handling

***

# 4. Basic Error Handling (`try` / `except`)

Used to handle runtime errors without crashing the program.

***

## Basic Syntax

```python theme={null}
try:
    # risky code
except:
    # runs if error occurs
```

***

## Example

```python theme={null}
try:
    print(10 / 0)
except:
    print("Cannot divide by zero")
```

Output

```text theme={null}
Cannot divide by zero
```

***

## Catch Specific Exceptions

```python theme={null}
try:
    number = int("abc")
except ValueError:
    print("Invalid number")
```

***

## Multiple Exceptions

```python theme={null}
try:
    x = 10 / 0
except ZeroDivisionError:
    print("Division Error")
except ValueError:
    print("Value Error")
```

***

## `else`

Runs only if no exception occurs.

```python theme={null}
try:
    x = 10 / 2
except ZeroDivisionError:
    print("Error")
else:
    print("Success")
```

Output

```text theme={null}
Success
```

***

## `finally`

Always executes.

```python theme={null}
try:
    print(10 / 2)
except:
    print("Error")
finally:
    print("Finished")
```

Output

```text theme={null}
5.0
Finished
```

***

## Raising Exceptions

```python theme={null}
age = -1

if age < 0:
    raise ValueError("Age cannot be negative")
```

***

## Common Built-in Exceptions

| Exception           | Description              |
| :------------------ | :----------------------- |
| `ValueError`        | Wrong value type         |
| `TypeError`         | Wrong data type          |
| `NameError`         | Variable not defined     |
| `IndexError`        | Invalid list index       |
| `KeyError`          | Invalid dictionary key   |
| `ZeroDivisionError` | Division by zero         |
| `FileNotFoundError` | File not found           |
| `AttributeError`    | Invalid object attribute |

***

# Quick Revision

### Error Handling

* `try` → Code that may fail.
* `except` → Handle exceptions.
* `else` → Runs when no exception occurs.
* `finally` → Always runs.
* `raise` → Manually throw an exception.
* Catch specific exceptions whenever possible instead of using a bare `except`.