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AggregationOperation Protocol Reference
AggregationOperation
public protocol AggregationOperationAggregationOperation’s represent the per-group operations within a
“split-apply-combine” analysis. Types conforming to the
AggregationOperation protocol can be used as aggregation functions within
a “groupBy” operation.
Because AggregationOperations can be parallelized across multiple cores or
hosts, they must support a “merge” operation, which can be used to
aggregate the state within the operations themselves.
-
Undocumented
Declaration
Swift
associatedtype Input : PCSVParsible, PDefaultInit, PStringParsible, Comparable, Hashable -
Undocumented
Declaration
Swift
associatedtype Output : PCSVParsible, PDefaultInit, PStringParsible, Comparable, Hashable -
Update the aggregation statistics with a new cell.
Declaration
Swift
mutating func update(with cell: Input?) -
Merge state with another instance of this operation.
(e.g. the other cell will have been operating on another shard of the data frame in parallel.)
Declaration
Swift
mutating func merge(with other: Self) -
Compute the output results from this operation. This will be stored in a dataframe.
Declaration
Swift
func finish() -> Output?