Concepts to Know > Concepts to Know > Functions > ScalarValuedFunction
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ScalarValuedFunction
In DataFlow, functions are objects implementing the ScalarValuedFunction interface. A number of commonly used functions are available as part of the function library; predefined functions are listed in Available Functions.
As with operators, functions are intended to be used as a point of extension. Users can develop new functions that can be used in an identical fashion as those provided by the library. Defining a new function is not generally a matter of creating a new implementation of ScalarValuedFunction, however. See Writing a Function for information on creating new functions.
There are two contexts in which ScalarValuedFunction objects can be used:
• Constructing functions to use with an operator. This includes composing functions together to produce more complex ones. This is the most common use case, as two commonly used operators—Using the DeriveFields Operator to Compute New Fields and Using the FilterRows Operator to Filter by Predicate—use functions to configure their behavior.
• Evaluating a function against a record. This is a much less common usage, typically reserved for the implementation of function-based operators or unit testing of function implementations.
Last modified date: 12/09/2024