Anonymous function

 Anonymous function

Anonymous functions in Python are functions that are defined using the `lambda` keyword. Unlike named functions, anonymous functions do not have a specified name. They are often used for simple, one-off operations where defining a full named function is unnecessary or clutters the code.

### Syntax of an Anonymous Function (Lambda Function):

```python

lambda arguments: expression

```

- `lambda`: The keyword used to define an anonymous function.

- `arguments`: The input parameters or arguments.

- `expression`: The operation or calculation the function performs.

### Example of an Anonymous Function:

```python

# Anonymous function to calculate the square of a number

square = lambda x: x  ** 2

# Calling the anonymous function

result = square(5)

print("Square:", result)  # Output: Square: 25

```

In this example, we define an anonymous function using `lambda` to calculate the square of a number. We then call this anonymous function with the argument `5` and print the result.

### Use Cases for Anonymous Functions:

1. Simple Calculations:

   - When you need a quick calculation without defining a named function.

2. Sorting or Filtering:

   - In cases where you need to sort or filter data using a custom criterion, anonymous functions can be handy.

   ```python

   data = [(1, 'Alice'), (3, 'Charlie'), (2, 'Bob')]

   sorted_data = sorted(data, key=lambda x: x[0])

   print(sorted_data)  # Output: [(1, 'Alice'), (2, 'Bob'), (3, 'Charlie')]

   ```

3. Callbacks:

   - As arguments to higher-order functions that accept functions as parameters.

   ```python

   def apply_operation(operation, x, y):

       return operation(x, y)

   addition = lambda a, b: a + b

   multiplication = lambda a, b: a * b

   result_addition = apply_operation(addition, 3, 5)

   result_multiplication = apply_operation(multiplication, 3, 5)

   print("Addition:", result_addition)  # Output: Addition: 8

   print("Multiplication:", result_multiplication)  # Output: Multiplication: 15

   ```

Anonymous functions are particularly useful when the function logic is straightforward and does not require a detailed, named function. However, for more complex operations or functions that need to be reused, named functions are generally preferred.