Hi Fabian - Thanks Fabian, that is a helpful description.
That document WAS my source of information and it seems to also be the source of my confusion. Further, it appears to be wrong - there is a FoldFunction<O,T> ( https://ci.apache.org/projects/flink/flink-docs-release-0.10/api/java/org/apache/flink/api/common/functions/FoldFunction.html) that should be passed into fold()? Separate note: fold() doesn't appear in the javadocs for 0.10.0 DataStream (see https://ci.apache.org/projects/flink/flink-docs-release-0.10/api/java/org/apache/flink/streaming/api/datastream/DataStream.html). So this made me look in the freshly-downloaded flink-streaming-java:0.10.0 and fold() does not appear in org .apache.flink.streaming.api.datastream.DataStream either. Am I looking in the wrong place for it? In 0.9.1, it's located in that same class with this signature: fold(R initialValue, FoldFunction<OUT, R> folder). Ron On Wed, Nov 18, 2015 at 9:39 AM, Fabian Hueske <fhue...@gmail.com> wrote: > Hi Ron, > > Have you checked: > https://ci.apache.org/projects/flink/flink-docs-release-0.10/apis/streaming_guide.html#transformations > ? > > Fold is like reduce, except that you define a start element (of a > different type than the input type) and the result type is the type of the > initial value. In reduce, the result type must be identical to the input > type. > > Best, Fabian > > 2015-11-18 18:32 GMT+01:00 Ron Crocker <rcroc...@newrelic.com>: > >> Is there a succinct description of the distinction between these >> transforms? >> > -- Ron Crocker Principal Software Engineer ( ( •)) New Relic rcroc...@newrelic.com M: +1 630 363 8835
