Analytics of information often require a reduction of data volume, computing certain statistics of the data involved. Those operations are called aggregations, which turn a collection of objects into a singleton value, representing the original information that has been combined in one form or another.
Because all aggregates are conceptually the same, we start by looking at the general-purpose
Aggregate operator and discuss more specific aggregation operators later.
Aggregate operator takes a sequence of elements of type
T and turns them into a single value of another type
A, which stands for accumulated or aggregated depending on your choice of vocab. But how can we transform any number of elements of type
T into a ...