Use lambda functions, or "lambdas" for short, to express simple inline functions that can be applied to input values in various ways. For example, you could apply a lambda function to each element of a collection, resulting in a transformed output collection. Also, you can use lambdas to filter the elements of a collection, or reduce a collection to a single value. The advantage of a lambda is that you can express user-defined functionality in a way that doesn’t require implementing a full UDF.
Learn how to use lambda functions in the how-to guide.