What is a lambda function?

• A. A type of regular function
• B. A small anonymous function defined with the lambda keyword
• C. A function with no parameters
• D. A built-in Python function that handles exceptions

Answer: (B)

A lambda function is a small anonymous function defined using the lambda keyword in Python. It allows you to create a function in a very concise way, typically for single-use cases or where you need a simple function temporarily. Unlike regular functions defined with def, lambda functions can have any number of parameters but can only contain a single expression. This makes them particularly useful in places where a simple function is needed for a short period, such as in functional programming contexts like mapping, filtering, or sorting.

The key characteristics of lambda functions include their ability to be defined inline and their anonymous nature, which means they are not necessarily bound to a name unless you choose to assign them to a variable. This makes them efficient for simple operations without the overhead of defining a full function.

Regular functions, while versatile and capable of handling more complex logic, are not as succinct as lambda functions when it comes to generating quick, throwaway functions in the flow of your code. This distinction makes choosing lambda functions suitable for various applications where simplicity and brevity are paramount.

Other options such as a function with no parameters or a built-in function handling exceptions do not accurately reflect the definition and purpose of lambda functions in Python.