CODEWITHSUNDEEP
groovygremlin
andres_est83
andres_est83

Reputation: 45

Filter the list generated by a Gremlin traversal and Groovy

I'm doing the following traversal:

g.V().has('Transfer','eventName','Airdrop').as('t1').
outE('sent_to').
inV().dedup().as('a2').
inE('sent_from').
outV().as('t2').
where('t1',eq('t2')).by('address').
outE('sent_to').
inV().as('a3').
select('a3','a2').
by('accountId').toList().groupBy { it.a3 }.collectEntries { [(it.key): [a2 : it.value.a2]]};

So as you can see I'm basically doing a traversal and at the end I'm using groovy with collectEntries to aggregate the results like I need them, which is aggregated by a3 in this case. The results look like this:

==>0xfe43502662ce2adf86d9d49f25a27d65c70a709d={a2=[0x99feb505a8ed9976cf19e757a9536117e6cdc5ba, 0x22019ad32ea3adabae68003bdefd099d7e5e3886]}

(This is GOOD, because the number of values in a2 is at least 2)

==>0x129e0131ea3cc16fe5252d7280bd1258f629f20f={a2=[0xf7958fad496d15cf9fd9e54c0012504f4fdb96ff]}

(This is NOT GOOD, I want to return in my list only those combinations where there are at lest 2 values for a2)

I have tried using filters and an additional where step in the traversal itself but I haven't been able to do it. I'm not sure if this is something I should skip using Groovy in my last line. Any help or orientation would be very much appreciated

Upvotes: 0

Views: 165

Answers (2)

Onno Rouast
Onno Rouast

Reputation: 672

The easiest way to do this is with findAll { }.

.groupBy { it.a3 }
.findAll { it.value.a2.size() > 1 }
.collectEntries { [(it.key): [a2: it.value.a2]] }

if some a2 are null, then value.a2 also evaluates to null and filters the results without the need for explicit nullchecks

Upvotes: 0

stephen mallette
stephen mallette

Reputation: 46216

I don't think you need to drop into Groovy to get the answer you want. It would be preferable to do this all in Gremlin especially since you intend to filter results which could yield some performance benefit. Gremlin has it's own group() step as well as methods for filtering the resulting Map:

g.V().has('Transfer','eventName','Airdrop').as('t1').
  out('sent_to').
  dedup().as('a2').
  in('sent_from').as('t2').
  where('t1',eq('t2')).by('address').
  out('sent_to').inV().as('a3').
  select('a3','a2').
    by('accountId').
  group().
    by('a3').
    by('a2').
  unfold().
  where(select(values).limit(local,2).count(local).is(gte(2)))

The idea is to build your Map with group() then deconstruct it to entries with unfold(). You the filter each entry with where() by selecting the values of the entry, which is a List of "a2" then counting the items locally in that List. I use limit(local,2) to avoid unnecessary iteration beyond 2 since the filter is gte(2).

Upvotes: 3

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