First

Aggregator finding the first value

Processing

The first subject encountered is the result of the aggregation.

If no subjects are processed, the aggregation result is nil

Name Type Description

Name	Type	Description
Nil Handling	string	Defines how to handle `nil` values: ignore: skips `nil` values process: accepts `nil` values
NaN Handling	string	Defines how to handle `NaN` values: ignore: skips `NaN` values process: accepts `NaN` values

string

Defines how to handle nil values:

string

Defines how to handle NaN values:

This expression evaluates to a dict of the form:

{
  :init any,
  :acc function,
  :out function
}

The supplied values are consistent with aggregation semantics of the Group By step.