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https://issues.apache.org/jira/browse/TINKERPOP-1609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15832120#comment-15832120
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Daniel Kuppitz commented on TINKERPOP-1609:
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After a quick discussion with [~okram] it turned out that
{{.group("m").by(select("x","y")).by(select("z").tail(1))}} actually shows the
desired behavior. It's still strange to use {{group()}} for something that has
nothing to do with grouping, but I will close the ticket as we shouldn't
duplicate existing functionalities.
> Make store() support maps
> -------------------------
>
> Key: TINKERPOP-1609
> URL: https://issues.apache.org/jira/browse/TINKERPOP-1609
> Project: TinkerPop
> Issue Type: New Feature
> Components: process
> Affects Versions: 3.2.3
> Reporter: Daniel Kuppitz
>
> Let me start with an example. This is the betweeness centrality algorithm
> from our recipes docs:
> {noformat}
> g.V().as("v").
> repeat(both().simplePath().as("v")).emit().
> filter(project("x","y","z").by(select(first, "v")).
> by(select(last, "v")).
> by(select(all, "v").count(local)).as("triple").
> coalesce(select("x","y").as("a").
> select("triples").unfold().as("t").
> select("x","y").where(eq("a")).
> select("t"),
> store("triples")).
> select("z").as("length").
> select("triple").select("z").where(eq("length"))).
> select(all, "v").unfold().
> groupCount().next()
> {noformat}
> One compute intensive part is the unrolling of previously seen triples to see
> if a shortest path between a specific pair of vertices was already found. It
> would be smarter to store the vertex pair in a map (the key being the pair
> and value being the path length). For that reason I suggest that we make
> {{store()}} support maps by allowing more than one {{by()}} modulator.
> Furthermore we need the ability to select dynamic map keys, but that's
> another ticket. For this ticket focus on {{store()}} and ignore the nested
> {{select()}} in the following rewritten example:
> {noformat}
> g.V().as("v").
> repeat(both().simplePath().as("v")).emit().
> filter(project("x","y","z").by(select(first, "v")).
> by(select(last, "v")).
> by(select(all, "v").count(local)).as("triple").
> coalesce(select("m").select(select("x","y")),
> store("m").by(select("x","y")).
> by(select("z")).select("z")).as("length")
> select("triple").select("z").where(eq("length"))).
> select(all, "v").unfold().
> groupCount().next()
> {noformat}
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