What is Python Lambda and how to use it?

A **Python Lambda function** is a small anonymous function defined with the keyword `lambda`. Unlike normal functions defined using `def`, a lambda function is used for simple, one-liner functions, and doesn't require a name. It can take any number of arguments but can only have one expression.

### Syntax of a Lambda Function:

```python

lambda arguments: expression

```

- **arguments**: Parameters to the function

- **expression**: A single expression that the function will return

### How to Use Lambda Functions:

1. **Basic Example**:

   Here's a lambda function that adds 2 to a number.

   ```python

   add_two = lambda x: x + 2

   print(add_two(5))  # Output: 7

   ```

2. **Multiple Arguments**:

   You can have multiple arguments in a lambda function.

   ```python

   multiply = lambda a, b: a * b

   print(multiply(4, 3))  # Output: 12

   ```

3. **Use in Higher-Order Functions**:

   Lambda functions are often used with functions like `map()`, `filter()`, and `reduce()`.

   - **Using with `map()`**:

     ```python

     numbers = [1, 2, 3, 4]

     doubled = list(map(lambda x: x * 2, numbers))

     print(doubled)  # Output: [2, 4, 6, 8]

     ```

   - **Using with `filter()`**:

     ```python

     numbers = [1, 2, 3, 4, 5]

     even = list(filter(lambda x: x % 2 == 0, numbers))

     print(even)  # Output: [2, 4]

     ```

   - **Using with `reduce()`** (from the `functools` module):

     ```python

     from functools import reduce

     numbers = [1, 2, 3, 4]

     product = reduce(lambda x, y: x * y, numbers)

     print(product)  # Output: 24

     ```

### When to Use Lambda Functions:

- When you need a small function for a short period of time.

- Useful when passing simple functionality to higher-order functions.

- Avoid using lambda for complex logic—use `def` for readability and maintainability.

### Limitations:

- Lambdas are limited to a single expression. They cannot contain multiple statements.

- For more complex functions, it’s better to define a regular function using `def`.