Apache Spark Certification Practice Test

Lambda functions, also known as anonymous functions, are a concise way to define functions in programming. Their defining characteristic is that they can indeed be created in a single line of code. This makes lambda functions particularly useful for short-term functions that don’t require a formal declaration or multi-line body. Their syntax is typically simplified compared to traditional function definitions, allowing for more streamlined and readable code, especially when used in scenarios like functional programming, callbacks, or sorting.

The other statements do not accurately describe the nature of lambda functions. While they do not require a name—hence the term 'anonymous'—and can take parameters (just like regular functions), they can be employed in various programming paradigms, not just functional programming. Thus, the capability of being defined in a single line is a key feature that makes lambda functions distinctively useful.