On 6/29/17 10:21 AM, G. Allegri wrote: > > 1. Allowing multiple field selection for grouping > 2. Keeping attributes of first feature when grouping > > > I will accept this criteria, obviously, if it's the preferred solution > for the mosts. > I just want to report that many users (partecipants to courses or > customers) say they find having the "first feature value" misleading. > I agree with them. I would set the field values only for the grouping > fields, having the same value within the group, and set null for the > other fields. > > The problem raises during a long workflow. At some point you obtain a > dataset with unconsisten field values, and it's not always obvious to > know when and.which field value was set miningless.
In the long run the most flexible solution will be to allow specifying the aggregate function applied to each field individually ("first/any", "mean", "mode", "max"...). No worries if it's not implemented right now, but please keep the code modular enough to introduce this easily later down the road. Without manually editing each algorithm that supports grouping. A possible approach to this would be a parameter "ParamterFieldAggregation" that offers a standard gui to configure the aggregation behavior (fieldA: min; fieldB: mean; fieldC: any; fieldD: mean(expression("numBirds2017 - numBirds2000")) ). Matthias
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