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Posted to dev@tinkerpop.apache.org by spmallette <gi...@git.apache.org> on 2017/01/10 18:50:47 UTC
[GitHub] tinkerpop pull request #531: Added more recipes
GitHub user spmallette opened a pull request:
https://github.com/apache/tinkerpop/pull/531
Added more recipes
There's no JIRA ticket for this. It's just a random bunch of additions to the recipes documentation. Note that in this update i added an "Appendix" which simply contains some "complex" or otherwise "interesting" traversals that don't seem to fit a pattern/recipe, but remain potentially useful for learning.
I've published the docs here for review:
http://tinkerpop.apache.org/docs/3.2.4-SNAPSHOT/recipes/
VOTE +1
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/apache/tinkerpop more-recipes
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/tinkerpop/pull/531.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #531
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by okram <gi...@git.apache.org>.
Github user okram commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95564117
--- Diff: docs/src/recipes/connected-components.asciidoc ---
@@ -0,0 +1,82 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+[[connected-components]]
+Connected Components
+--------------------
+
+Gremlin can be used to find link:https://en.wikipedia.org/wiki/Connected_component_(graph_theory)[connected components]
+in a graph. Consider the following graph which has three connected components:
+
+image:connected-components.png[width=600]
+
+[gremlin-groovy]
+----
+g.addV(id, "A").as("a").
+ addV(id, "B").as("b").
+ addV(id, "C").as("c").
+ addV(id, "D").as("d").
+ addV(id, "E").as("e").
+ addV(id, "F").
+ addE("link").from("a").to("b").
+ addE("link").from("b").to("c").
+ addE("link").from("d").to("e").iterate()
+----
+
+One way to detect the various subgraphs would be to do something like this:
+
+[gremlin-groovy,existing]
+----
+g.V().emit(cyclicPath().or().not(both())).repeat(both()).until(cyclicPath()). <1>
+ aggregate("p").by(path()).cap("p"). <2>
+ unfold().limit(local, 1).dedup(). <3>
+ map(__.as("v").select("p").unfold(). <4>
+ filter(unfold().where(eq("v"))).
+ unfold().dedup().order().by(id).fold()
+ ).dedup() <5>
+----
+
+<1> Iterate all vertices and repeatedly traverse over both incoming and outgoing edges (TinkerPop doesn't support
+unidirectional graphs directly so it must be simulated by ignoring the direction with `both`). Note the use of `emit`
+prior to `repeat` as this allows for return of a single length path.
+<2> Aggregate the emitted vertices to "p" and get their path information. Calling `cap` at the end will push the
+aggregate path list into the traversal. It is within these paths that the list of connected components will be
+identified. Obviously the paths list are duplicative in the sense that they contains different paths travelled over
+the same vertices.
+<3> Unroll the elements in the path list with `unfold` and grab the first vertex in each path and `dedup`.
+<4> Use the first vertex in each path to filter against the paths stored in "p". When a path is found that has the
+vertex in it, dedup the vertices in the path, order it by the identifier. Each path output from this `map` step
+represents a connected component.
+<5> The connected component list is duplicative given the nature of the paths in "p", but now that the vertices within
+the paths are ordered, a final `dedup` will make the list of connective components unique.
+
+NOTE: This is a nice example of where running smaller pieces of a large Gremlin statement make it easier to see what
+is happening at each step. Consider running this example one line at a time (or perhaps even in a step at a time) to
+see the output at each point.
+
+While the above approach returns results nicely, the traversal doesn't appear to work with OLAP. A less efficient
+approach, but one more suited for OLAP execution looks quite similar but does not use `dedup` as heavily (thus
+`GraphComputer` is forced to analyze far more paths):
+
+[gremlin-groovy,existing]
+----
+g.withComputer().V().emit(cyclicPath().or().not(both())).repeat(both()).until(cyclicPath()).
--- End diff --
I ran your "OLTP" traversal `withComputer()` and it works as expected.. ?
```
gremlin> g.withComputer().V().emit(cyclicPath().or().not(both())).repeat(both()).until(cyclicPath()).
......1> aggregate("p").by(path()).cap("p").
......2> unfold().limit(local, 1).dedup().
......3> map(__.as("v").select("p").unfold().
......4> filter(unfold().where(eq("v"))).
......5> unfold().dedup().order().by(id).fold()
......6> ).dedup()
==>[v[A],v[B],v[C]]
==>[v[D],v[E]]
==>[v[F]]
```
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by okram <gi...@git.apache.org>.
Github user okram commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95562939
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
+contains a number of traversals from the mailing list that do not easily fit any particular pattern (i.e. a recipe),
+but are nonetheless interesting and thus remain good tools for learning Gremlin.
+
+[[appendix-a]]
+_For each person in a "follows" graph, determine the number of followers and list their names._
+
+[gremlin-groovy]
+----
+g.addV('name','marko').as('marko').
+ addV('name','josh').as('josh').
+ addV('name','daniel').as('daniel').
+ addV('name','matthias').as('matthias').
+ addE('follows').from('josh').to('marko').
+ addE('follows').from('matthias').to('josh').
+ addE('follows').from('daniel').to('josh').
+ addE('follows').from('daniel').to('marko').iterate()
+g.V().as('p').
--- End diff --
You could also show another version.
```
g.V().group().
by('name').
by(project('numFollowers','followers').
by(__.in('follows').count()).
by(__.in('follows').values('name').fold())).next()
```
or yet another version....
```
g.V().group().
by('name').
by(__.in('follows').values('name').fold().
project('numFollowers','followers').
by(count(local)).
by()).next()
```
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by dkuppitz <gi...@git.apache.org>.
Github user dkuppitz commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95638679
--- Diff: docs/src/recipes/connected-components.asciidoc ---
@@ -0,0 +1,82 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+[[connected-components]]
+Connected Components
+--------------------
+
+Gremlin can be used to find link:https://en.wikipedia.org/wiki/Connected_component_(graph_theory)[connected components]
+in a graph. Consider the following graph which has three connected components:
+
+image:connected-components.png[width=600]
+
+[gremlin-groovy]
+----
+g.addV(id, "A").as("a").
+ addV(id, "B").as("b").
+ addV(id, "C").as("c").
+ addV(id, "D").as("d").
+ addV(id, "E").as("e").
+ addV(id, "F").
+ addE("link").from("a").to("b").
+ addE("link").from("b").to("c").
+ addE("link").from("d").to("e").iterate()
+----
+
+One way to detect the various subgraphs would be to do something like this:
+
+[gremlin-groovy,existing]
+----
+g.V().emit(cyclicPath().or().not(both())).repeat(both()).until(cyclicPath()). <1>
+ aggregate("p").by(path()).cap("p"). <2>
+ unfold().limit(local, 1).dedup(). <3>
+ map(__.as("v").select("p").unfold(). <4>
+ filter(unfold().where(eq("v"))).
+ unfold().dedup().order().by(id).fold()
+ ).dedup() <5>
+----
+
+<1> Iterate all vertices and repeatedly traverse over both incoming and outgoing edges (TinkerPop doesn't support
+unidirectional graphs directly so it must be simulated by ignoring the direction with `both`). Note the use of `emit`
+prior to `repeat` as this allows for return of a single length path.
+<2> Aggregate the emitted vertices to "p" and get their path information. Calling `cap` at the end will push the
+aggregate path list into the traversal. It is within these paths that the list of connected components will be
+identified. Obviously the paths list are duplicative in the sense that they contains different paths travelled over
+the same vertices.
+<3> Unroll the elements in the path list with `unfold` and grab the first vertex in each path and `dedup`.
+<4> Use the first vertex in each path to filter against the paths stored in "p". When a path is found that has the
+vertex in it, dedup the vertices in the path, order it by the identifier. Each path output from this `map` step
+represents a connected component.
+<5> The connected component list is duplicative given the nature of the paths in "p", but now that the vertices within
+the paths are ordered, a final `dedup` will make the list of connective components unique.
+
+NOTE: This is a nice example of where running smaller pieces of a large Gremlin statement make it easier to see what
+is happening at each step. Consider running this example one line at a time (or perhaps even in a step at a time) to
+see the output at each point.
+
+While the above approach returns results nicely, the traversal doesn't appear to work with OLAP. A less efficient
+approach, but one more suited for OLAP execution looks quite similar but does not use `dedup` as heavily (thus
+`GraphComputer` is forced to analyze far more paths):
+
+[gremlin-groovy,existing]
+----
+g.withComputer().V().emit(cyclicPath().or().not(both())).repeat(both()).until(cyclicPath()).
--- End diff --
I'm pretty sure that's not working in `tp32` (OLAP).
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by okram <gi...@git.apache.org>.
Github user okram commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95563597
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
+contains a number of traversals from the mailing list that do not easily fit any particular pattern (i.e. a recipe),
+but are nonetheless interesting and thus remain good tools for learning Gremlin.
+
+[[appendix-a]]
+_For each person in a "follows" graph, determine the number of followers and list their names._
+
+[gremlin-groovy]
+----
+g.addV('name','marko').as('marko').
+ addV('name','josh').as('josh').
+ addV('name','daniel').as('daniel').
+ addV('name','matthias').as('matthias').
+ addE('follows').from('josh').to('marko').
+ addE('follows').from('matthias').to('josh').
+ addE('follows').from('daniel').to('josh').
+ addE('follows').from('daniel').to('marko').iterate()
+g.V().as('p').
+ map(__.in('follows').values('name').fold()).
+ group().by(select('p').by('name')).
+ by(project('numFollowers','followers').
+ by(count(local)).by()).next()
+----
+
+[[appendix-b]]
+_In the "modern" graph, show each person, the software they worked on and the co-worker count for the software and
+the names of those co-workers._
+
+[gremlin-groovy,modern]
+----
+g.V().hasLabel("person").as("p").
+ out("created").as("s").
+ map(__.in("created").
+ where(neq("p")).values("name").fold()).
+ group().by(select("p").by("name")).
+ by(group().by(select("s").by("name")).
+ by(project("numCoworkers","coworkers").
+ by(count(local)).by())).next()
+----
+
+[[appendix-c]]
+_Assuming a graph of students, classes and times, detect students who have a conflicting schedule._
+
+[gremlin-groovy]
+----
+g.addV(label, "student", "name", "Pete").as("s1").
+ addV(label, "student", "name", "Joe").as("s2").
+ addV(label, "class", "name", "Java's GC").as("c1").
+ addV(label, "class", "name", "FP Principles").as("c2").
+ addV(label, "class", "name", "Memory Management in C").as("c3").
+ addV(label, "class", "name", "Memory Management in C++").as("c4").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "10:00", "toTime", "11:00").as("t1").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "11:00", "toTime", "12:00").as("t2").
+ addE("attends").from("s1").to("c1").
+ addE("attends").from("s1").to("c2").
+ addE("attends").from("s1").to("c3").
+ addE("attends").from("s1").to("c4").
+ addE("attends").from("s2").to("c2").
+ addE("attends").from("s2").to("c3").
+ addE("allocated").from("c1").to("t1").
+ addE("allocated").from("c1").to("t2").
+ addE("allocated").from("c2").to("t1").
+ addE("allocated").from("c3").to("t2").
+ addE("allocated").from("c4").to("t2").iterate()
+g.V().hasLabel("student").as("s").
+ out("attends").as("c").
+ out("allocated").as("t").
+ select("s").
+ out("attends").
+ where(neq("c")).
+ out("allocated").
+ where(eq("t")).
+ group().
+ by(select("s").by("name")).
+ by(group().by(select("t").by(valueMap("fromTime","toTime"))).
+ by(select("c").dedup().values("name").fold())).next()
+----
+
+[[appendix-d]]
+_In the "modern" graph, with a duplicate edge added, find the vertex pairs that have more than one edge between them._
+
+[gremlin-groovy,modern]
+----
+g.V(1).as("a").V(3).addE("created").property("weight",0.4d).from("a").iterate()
+g.V(1).outE("created")
+g.V().as("a").
+ out().as("b").
+ groupCount().
+ by(select("a","b")).
+ unfold().
+ filter(select(values).is(gt(1))).
+ select(keys)
+----
+
+[[appendix-e]]
+_In the "crew" graph, find vertices that match on a complete set of multi-properties._
+
+[gremlin-groovy,theCrew]
+----
+places = ["centreville","dulles"];[] // will not match as "purcellville" is missing
+g.V().not(has("location", without(places))).
+ where(values("location").is(within(places)).count().is(places.size())).
+ valueMap()
+places = ["centreville","dulles","purcellville"];[]
+g.V().not(has("location", without(places))).
+ where(values("location").is(within(places)).count().is(places.size())).
+ valueMap()
+----
+
+[[appendix-f]]
+_Methods for performing some basic mathematical operations in the "modern" graph._
+
+[gremlin-groovy,modern]
+----
+g.V().values("age").sum() // sum all ages
+g.V().values("age").fold(1, mult) // multiply all ages
+g.V().values("age").map(union(identity(), constant(-1)).sum()) // subtract 1
+g.V().values("age").map(union(identity(), identity()).sum()) // multiply by 2 (simple)
+g.V().values("age").map(union(identity(), constant(2)).fold(1, mult)) // multiply by 2 (generally useful for multiplications by n):
+----
+
+[[appendix-g]]
+_Dropping a vertex, as well as the vertices related to that dropped vertex that are connected by a "knows" edge in the
+"modern" graph_
+
+[gremlin-groovy,modern]
+----
+g.V().has('name','marko').outE()
+g.V().has('name','marko').sideEffect(out('knows').drop()).drop()
+g.V().has('name','marko')
+g.V(2,4,3)
+----
+
+[[appendix-h]]
+_For the specified graph, find all neighbor vertices connected to "A" as filtered by datetime, those neighbor vertices
+that don't have datetime vertices, and those neighbor vertices that have the label "dimon"._
+
+[gremlin-groovy]
+----
+g.addV().property("name", "A").as("a").
+ addV().property("name", "B").as("b").
+ addV().property("name", "C").as("c").
+ addV().property("name", "D").as("d").
+ addV().property("name", "E").as("e").
+ addV("dimon").property("name", "F").as("f").
+ addV().property("name", "G").as("g").property("date", 20160818).
+ addV().property("name", "H").as("h").property("date", 20160817).
+ addE("rel").from("a").to("b").
+ addE("rel").from("a").to("c").
+ addE("rel").from("a").to("d").
+ addE("rel").from("a").to("e").
+ addE("rel").from("c").to("f").
+ addE("occured_at").from("d").to("g").
+ addE("occured_at").from("e").to("h").iterate()
+// D and E have a valid datetime
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", gte(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// only E has a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", lte(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// only D has a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", gt(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// neither D nor E have a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", lt(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+----
+
+[[appendix-i]]
+_Use element labels in a `select`._
+
+[gremlin-groovy,modern]
+----
+g.V(1).as("a").
+ both().
+ map(group().by(label).by(unfold())).as("b").
+ select("a","b").
+ map(union(project("a").by(select("a")), select("b")).
+ unfold().
+ group().
+ by(select(keys)).
+ by(select(values)))
+g.V().as("a").
+ both().
+ map(group().by(label).by(unfold())).as("b").
+ select("a","b").
+ group().
+ by(select("a")).
+ by(select("b").
+ group().
+ by(select(keys)).
+ by(select(values).fold())).
+ unfold().
+ map(union(select(keys).project("a").by(), select(values)).
+ unfold().
+ group().
+ by(select(keys).unfold()).
+ by(select(values).unfold().unfold().fold()))
+----
--- End diff --
I'm wondering if some of these traversals may "look better" with `match()`. @dkuppitz ?
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[GitHub] tinkerpop issue #531: Added more recipes
Posted by spmallette <gi...@git.apache.org>.
Github user spmallette commented on the issue:
https://github.com/apache/tinkerpop/pull/531
I'm not so sure how good I am at Gremlin - a good portion of this stuff comes from @dkuppitz answers :smile: - but I'm better at Gremlin for sure after writing these recipes as I'm forced to really analyze and question what's going on in the traversals so that I can write a proper narrative. Of course, it still is a fair bit of work to write all this up, organize it into patterns, sometimes re-write traversals or data to better fit the narrative, etc. so I won't argue about that.
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by okram <gi...@git.apache.org>.
Github user okram commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95565322
--- Diff: docs/src/recipes/duplicate-edge.asciidoc ---
@@ -0,0 +1,142 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+[[duplicate-edge]]
+Duplicate Edge Detection
+------------------------
+
+Whether part of a graph maintenance process or for some other analysis need, it is sometimes necessary to detect
+if there is more than one edge between two vertices. The following examples will assume that an edge with the same
+label and direction will be considered "duplicate".
+
+The "modern" graph does not have any duplicate edges that fit that definition, so the following example adds one
+that is duplicative of the "created" edge between vertex "1" and "3".
+
+[gremlin-groovy,modern]
+----
+g.V(1).as("a").V(3).addE("created").from("a").iterate()
+g.V(1).outE("created")
+----
+
+One way to find the duplicate edges would be to do something like this:
+
+[gremlin-groovy,existing]
+----
+g.V().outE().
+ project("a","b"). <1>
+ by().by(inV().path().by().by(label)).
+ group(). <2>
+ by(select("b")).
+ by(select("a").fold()).
+ unfold(). <3>
+ select(values). <4>
+ where(count(local).is(gt(1)))
+----
+
+<1> The "a" and "b" from the `project` contain the edge and the path respectively. The path consists of a the outgoing
+vertex, an edge, and the incoming vertex. The use of `by().by(label))` converts the edge to its label (recall that `by`
+are applied in round-robin fashion), so the path will look something like: `[v[1],created,v[3]]`.
+<2> Group by the path from "b" and construct a list of edges from "a". Any value in this `Map` that has a list of edges
+greater than one means that there is more than one edge for that edge label between those two vertices (i.e. the `Map`
+key).
+<3> Unroll the key-value pairs in the `Map` of paths-edges.
+<4> Only the values from the `Map` are needed and as mentioned earlier, those lists with more than one edge would
+containa duplicate.
+
+This method find the duplicates, but does require more memory than other approaches. A slightly more complex approach
+that uses less memory might look like this:
+
+[gremlin-groovy,existing]
+----
+g.V().as("ov").
--- End diff --
Here is the `match()`-form.
```
g.V().match(
__.as("ov").outE().as("e"),
__.as("e").inV().as("iv"),
__.as("iv").inE().as("ie"),
__.as("ie").outV().as("ov")).
where("ie",neq("e")).
where("ie",eq("e")).by(label).
select("ie").
group().
by(select("ov","e","iv").by().by(label)).
unfold().select(values).
where(count(local).is(gt(1)))
```
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by spmallette <gi...@git.apache.org>.
Github user spmallette commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95781687
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
--- End diff --
i misread - got it
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[GitHub] tinkerpop issue #531: Added more recipes
Posted by spmallette <gi...@git.apache.org>.
Github user spmallette commented on the issue:
https://github.com/apache/tinkerpop/pull/531
Thanks for all the feedback. I've pushed some changes on this branch given the comments I've seen. I think I got all of it. Good to vote now?
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by dkuppitz <gi...@git.apache.org>.
Github user dkuppitz commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95639012
--- Diff: docs/src/recipes/duplicate-edge.asciidoc ---
@@ -0,0 +1,142 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+[[duplicate-edge]]
+Duplicate Edge Detection
+------------------------
+
+Whether part of a graph maintenance process or for some other analysis need, it is sometimes necessary to detect
+if there is more than one edge between two vertices. The following examples will assume that an edge with the same
+label and direction will be considered "duplicate".
+
+The "modern" graph does not have any duplicate edges that fit that definition, so the following example adds one
+that is duplicative of the "created" edge between vertex "1" and "3".
+
+[gremlin-groovy,modern]
+----
+g.V(1).as("a").V(3).addE("created").from("a").iterate()
+g.V(1).outE("created")
+----
+
+One way to find the duplicate edges would be to do something like this:
+
+[gremlin-groovy,existing]
+----
+g.V().outE().
+ project("a","b"). <1>
+ by().by(inV().path().by().by(label)).
+ group(). <2>
+ by(select("b")).
+ by(select("a").fold()).
+ unfold(). <3>
+ select(values). <4>
+ where(count(local).is(gt(1)))
+----
+
+<1> The "a" and "b" from the `project` contain the edge and the path respectively. The path consists of a the outgoing
+vertex, an edge, and the incoming vertex. The use of `by().by(label))` converts the edge to its label (recall that `by`
+are applied in round-robin fashion), so the path will look something like: `[v[1],created,v[3]]`.
+<2> Group by the path from "b" and construct a list of edges from "a". Any value in this `Map` that has a list of edges
+greater than one means that there is more than one edge for that edge label between those two vertices (i.e. the `Map`
+key).
+<3> Unroll the key-value pairs in the `Map` of paths-edges.
+<4> Only the values from the `Map` are needed and as mentioned earlier, those lists with more than one edge would
+containa duplicate.
+
+This method find the duplicates, but does require more memory than other approaches. A slightly more complex approach
+that uses less memory might look like this:
+
+[gremlin-groovy,existing]
+----
+g.V().as("ov").
--- End diff --
Go home.........
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[GitHub] tinkerpop issue #531: Added more recipes
Posted by okram <gi...@git.apache.org>.
Github user okram commented on the issue:
https://github.com/apache/tinkerpop/pull/531
VOTE +1.
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by spmallette <gi...@git.apache.org>.
Github user spmallette commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95641629
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
+contains a number of traversals from the mailing list that do not easily fit any particular pattern (i.e. a recipe),
+but are nonetheless interesting and thus remain good tools for learning Gremlin.
+
+[[appendix-a]]
+_For each person in a "follows" graph, determine the number of followers and list their names._
+
+[gremlin-groovy]
+----
+g.addV('name','marko').as('marko').
+ addV('name','josh').as('josh').
+ addV('name','daniel').as('daniel').
+ addV('name','matthias').as('matthias').
+ addE('follows').from('josh').to('marko').
+ addE('follows').from('matthias').to('josh').
+ addE('follows').from('daniel').to('josh').
+ addE('follows').from('daniel').to('marko').iterate()
+g.V().as('p').
+ map(__.in('follows').values('name').fold()).
+ group().by(select('p').by('name')).
+ by(project('numFollowers','followers').
+ by(count(local)).by()).next()
+----
+
+[[appendix-b]]
+_In the "modern" graph, show each person, the software they worked on and the co-worker count for the software and
+the names of those co-workers._
+
+[gremlin-groovy,modern]
+----
+g.V().hasLabel("person").as("p").
+ out("created").as("s").
+ map(__.in("created").
+ where(neq("p")).values("name").fold()).
+ group().by(select("p").by("name")).
+ by(group().by(select("s").by("name")).
+ by(project("numCoworkers","coworkers").
+ by(count(local)).by())).next()
+----
+
+[[appendix-c]]
+_Assuming a graph of students, classes and times, detect students who have a conflicting schedule._
+
+[gremlin-groovy]
+----
+g.addV(label, "student", "name", "Pete").as("s1").
+ addV(label, "student", "name", "Joe").as("s2").
+ addV(label, "class", "name", "Java's GC").as("c1").
+ addV(label, "class", "name", "FP Principles").as("c2").
+ addV(label, "class", "name", "Memory Management in C").as("c3").
+ addV(label, "class", "name", "Memory Management in C++").as("c4").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "10:00", "toTime", "11:00").as("t1").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "11:00", "toTime", "12:00").as("t2").
+ addE("attends").from("s1").to("c1").
+ addE("attends").from("s1").to("c2").
+ addE("attends").from("s1").to("c3").
+ addE("attends").from("s1").to("c4").
+ addE("attends").from("s2").to("c2").
+ addE("attends").from("s2").to("c3").
+ addE("allocated").from("c1").to("t1").
+ addE("allocated").from("c1").to("t2").
+ addE("allocated").from("c2").to("t1").
+ addE("allocated").from("c3").to("t2").
+ addE("allocated").from("c4").to("t2").iterate()
+g.V().hasLabel("student").as("s").
+ out("attends").as("c").
+ out("allocated").as("t").
+ select("s").
+ out("attends").
+ where(neq("c")).
+ out("allocated").
+ where(eq("t")).
+ group().
+ by(select("s").by("name")).
+ by(group().by(select("t").by(valueMap("fromTime","toTime"))).
+ by(select("c").dedup().values("name").fold())).next()
+----
+
+[[appendix-d]]
+_In the "modern" graph, with a duplicate edge added, find the vertex pairs that have more than one edge between them._
+
+[gremlin-groovy,modern]
+----
+g.V(1).as("a").V(3).addE("created").property("weight",0.4d).from("a").iterate()
+g.V(1).outE("created")
+g.V().as("a").
+ out().as("b").
+ groupCount().
+ by(select("a","b")).
+ unfold().
+ filter(select(values).is(gt(1))).
+ select(keys)
+----
+
+[[appendix-e]]
+_In the "crew" graph, find vertices that match on a complete set of multi-properties._
+
+[gremlin-groovy,theCrew]
+----
+places = ["centreville","dulles"];[] // will not match as "purcellville" is missing
+g.V().not(has("location", without(places))).
+ where(values("location").is(within(places)).count().is(places.size())).
+ valueMap()
+places = ["centreville","dulles","purcellville"];[]
+g.V().not(has("location", without(places))).
+ where(values("location").is(within(places)).count().is(places.size())).
+ valueMap()
+----
+
+[[appendix-f]]
+_Methods for performing some basic mathematical operations in the "modern" graph._
+
+[gremlin-groovy,modern]
+----
+g.V().values("age").sum() // sum all ages
+g.V().values("age").fold(1, mult) // multiply all ages
+g.V().values("age").map(union(identity(), constant(-1)).sum()) // subtract 1
+g.V().values("age").map(union(identity(), identity()).sum()) // multiply by 2 (simple)
+g.V().values("age").map(union(identity(), constant(2)).fold(1, mult)) // multiply by 2 (generally useful for multiplications by n):
+----
+
+[[appendix-g]]
+_Dropping a vertex, as well as the vertices related to that dropped vertex that are connected by a "knows" edge in the
+"modern" graph_
+
+[gremlin-groovy,modern]
+----
+g.V().has('name','marko').outE()
+g.V().has('name','marko').sideEffect(out('knows').drop()).drop()
+g.V().has('name','marko')
+g.V(2,4,3)
+----
+
+[[appendix-h]]
+_For the specified graph, find all neighbor vertices connected to "A" as filtered by datetime, those neighbor vertices
+that don't have datetime vertices, and those neighbor vertices that have the label "dimon"._
+
+[gremlin-groovy]
+----
+g.addV().property("name", "A").as("a").
+ addV().property("name", "B").as("b").
+ addV().property("name", "C").as("c").
+ addV().property("name", "D").as("d").
+ addV().property("name", "E").as("e").
+ addV("dimon").property("name", "F").as("f").
+ addV().property("name", "G").as("g").property("date", 20160818).
+ addV().property("name", "H").as("h").property("date", 20160817).
+ addE("rel").from("a").to("b").
+ addE("rel").from("a").to("c").
+ addE("rel").from("a").to("d").
+ addE("rel").from("a").to("e").
+ addE("rel").from("c").to("f").
+ addE("occured_at").from("d").to("g").
+ addE("occured_at").from("e").to("h").iterate()
+// D and E have a valid datetime
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", gte(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// only E has a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", lte(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// only D has a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", gt(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// neither D nor E have a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", lt(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+----
+
+[[appendix-i]]
+_Use element labels in a `select`._
+
+[gremlin-groovy,modern]
+----
+g.V(1).as("a").
+ both().
+ map(group().by(label).by(unfold())).as("b").
+ select("a","b").
+ map(union(project("a").by(select("a")), select("b")).
+ unfold().
+ group().
+ by(select(keys)).
+ by(select(values)))
+g.V().as("a").
+ both().
+ map(group().by(label).by(unfold())).as("b").
+ select("a","b").
+ group().
+ by(select("a")).
+ by(select("b").
+ group().
+ by(select(keys)).
+ by(select(values).fold())).
+ unfold().
+ map(union(select(keys).project("a").by(), select(values)).
+ unfold().
+ group().
+ by(select(keys).unfold()).
+ by(select(values).unfold().unfold().fold()))
+----
--- End diff --
I wonder if our lack of and extensive set of `match()` examples continues to create the sense that we don't have a declarative story for Gremlin.
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by dkuppitz <gi...@git.apache.org>.
Github user dkuppitz commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95785972
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
+contains a number of traversals from the mailing list that do not easily fit any particular pattern (i.e. a recipe),
+but are nonetheless interesting and thus remain good tools for learning Gremlin.
+
+[[appendix-a]]
+_For each person in a "follows" graph, determine the number of followers and list their names._
+
+[gremlin-groovy]
+----
+g.addV('name','marko').as('marko').
+ addV('name','josh').as('josh').
+ addV('name','daniel').as('daniel').
+ addV('name','matthias').as('matthias').
+ addE('follows').from('josh').to('marko').
+ addE('follows').from('matthias').to('josh').
+ addE('follows').from('daniel').to('josh').
+ addE('follows').from('daniel').to('marko').iterate()
+g.V().as('p').
+ map(__.in('follows').values('name').fold()).
+ group().by(select('p').by('name')).
+ by(project('numFollowers','followers').
+ by(count(local)).by()).next()
+----
+
+[[appendix-b]]
+_In the "modern" graph, show each person, the software they worked on and the co-worker count for the software and
+the names of those co-workers._
+
+[gremlin-groovy,modern]
+----
+g.V().hasLabel("person").as("p").
+ out("created").as("s").
+ map(__.in("created").
+ where(neq("p")).values("name").fold()).
+ group().by(select("p").by("name")).
+ by(group().by(select("s").by("name")).
+ by(project("numCoworkers","coworkers").
+ by(count(local)).by())).next()
+----
+
+[[appendix-c]]
+_Assuming a graph of students, classes and times, detect students who have a conflicting schedule._
+
+[gremlin-groovy]
+----
+g.addV(label, "student", "name", "Pete").as("s1").
+ addV(label, "student", "name", "Joe").as("s2").
+ addV(label, "class", "name", "Java's GC").as("c1").
+ addV(label, "class", "name", "FP Principles").as("c2").
+ addV(label, "class", "name", "Memory Management in C").as("c3").
+ addV(label, "class", "name", "Memory Management in C++").as("c4").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "10:00", "toTime", "11:00").as("t1").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "11:00", "toTime", "12:00").as("t2").
+ addE("attends").from("s1").to("c1").
+ addE("attends").from("s1").to("c2").
+ addE("attends").from("s1").to("c3").
+ addE("attends").from("s1").to("c4").
+ addE("attends").from("s2").to("c2").
+ addE("attends").from("s2").to("c3").
+ addE("allocated").from("c1").to("t1").
+ addE("allocated").from("c1").to("t2").
+ addE("allocated").from("c2").to("t1").
+ addE("allocated").from("c3").to("t2").
+ addE("allocated").from("c4").to("t2").iterate()
+g.V().hasLabel("student").as("s").
+ out("attends").as("c").
+ out("allocated").as("t").
+ select("s").
+ out("attends").
+ where(neq("c")).
+ out("allocated").
+ where(eq("t")).
+ group().
+ by(select("s").by("name")).
+ by(group().by(select("t").by(valueMap("fromTime","toTime"))).
+ by(select("c").dedup().values("name").fold())).next()
+----
+
+[[appendix-d]]
+_In the "modern" graph, with a duplicate edge added, find the vertex pairs that have more than one edge between them._
--- End diff --
I think it's important to note that this is only for edge that point into the same direction (`OUT` in the example). The solution for undirected edges is pretty complicated (if we take into account that ids are not necessarily sortable).
```
g.V().as("a").both().as("b").
groupCount().by(select("a","b")).unfold().
filter(select(values).is(gt(1))).
select(keys).not(__.as("x").select("done").unfold().as("y").
select("x","y").by(select("a")).by(select("b")).
where("x", eq("y"))).store("done")
```
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by asfgit <gi...@git.apache.org>.
Github user asfgit closed the pull request at:
https://github.com/apache/tinkerpop/pull/531
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by dkuppitz <gi...@git.apache.org>.
Github user dkuppitz commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95783275
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
+contains a number of traversals from the mailing list that do not easily fit any particular pattern (i.e. a recipe),
+but are nonetheless interesting and thus remain good tools for learning Gremlin.
+
+[[appendix-a]]
+_For each person in a "follows" graph, determine the number of followers and list their names._
+
+[gremlin-groovy]
+----
+g.addV('name','marko').as('marko').
+ addV('name','josh').as('josh').
+ addV('name','daniel').as('daniel').
+ addV('name','matthias').as('matthias').
+ addE('follows').from('josh').to('marko').
+ addE('follows').from('matthias').to('josh').
+ addE('follows').from('daniel').to('josh').
+ addE('follows').from('daniel').to('marko').iterate()
+g.V().as('p').
--- End diff --
`group()` is actually not needed here. `p` will be unique in the result, hence it's just a projection:
```
g.V().as('p').map(__.in('follows').values('name').fold()).
project('person','followers','numFollowers').by(select('p')).by('name')).by().by(count(local))
```
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by dkuppitz <gi...@git.apache.org>.
Github user dkuppitz commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95637868
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
+contains a number of traversals from the mailing list that do not easily fit any particular pattern (i.e. a recipe),
+but are nonetheless interesting and thus remain good tools for learning Gremlin.
+
+[[appendix-a]]
+_For each person in a "follows" graph, determine the number of followers and list their names._
+
+[gremlin-groovy]
+----
+g.addV('name','marko').as('marko').
+ addV('name','josh').as('josh').
+ addV('name','daniel').as('daniel').
+ addV('name','matthias').as('matthias').
+ addE('follows').from('josh').to('marko').
+ addE('follows').from('matthias').to('josh').
+ addE('follows').from('daniel').to('josh').
+ addE('follows').from('daniel').to('marko').iterate()
+g.V().as('p').
+ map(__.in('follows').values('name').fold()).
+ group().by(select('p').by('name')).
+ by(project('numFollowers','followers').
+ by(count(local)).by()).next()
+----
+
+[[appendix-b]]
+_In the "modern" graph, show each person, the software they worked on and the co-worker count for the software and
+the names of those co-workers._
+
+[gremlin-groovy,modern]
+----
+g.V().hasLabel("person").as("p").
+ out("created").as("s").
+ map(__.in("created").
+ where(neq("p")).values("name").fold()).
+ group().by(select("p").by("name")).
+ by(group().by(select("s").by("name")).
+ by(project("numCoworkers","coworkers").
+ by(count(local)).by())).next()
+----
+
+[[appendix-c]]
+_Assuming a graph of students, classes and times, detect students who have a conflicting schedule._
+
+[gremlin-groovy]
+----
+g.addV(label, "student", "name", "Pete").as("s1").
+ addV(label, "student", "name", "Joe").as("s2").
+ addV(label, "class", "name", "Java's GC").as("c1").
+ addV(label, "class", "name", "FP Principles").as("c2").
+ addV(label, "class", "name", "Memory Management in C").as("c3").
+ addV(label, "class", "name", "Memory Management in C++").as("c4").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "10:00", "toTime", "11:00").as("t1").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "11:00", "toTime", "12:00").as("t2").
+ addE("attends").from("s1").to("c1").
+ addE("attends").from("s1").to("c2").
+ addE("attends").from("s1").to("c3").
+ addE("attends").from("s1").to("c4").
+ addE("attends").from("s2").to("c2").
+ addE("attends").from("s2").to("c3").
+ addE("allocated").from("c1").to("t1").
+ addE("allocated").from("c1").to("t2").
+ addE("allocated").from("c2").to("t1").
+ addE("allocated").from("c3").to("t2").
+ addE("allocated").from("c4").to("t2").iterate()
+g.V().hasLabel("student").as("s").
+ out("attends").as("c").
+ out("allocated").as("t").
+ select("s").
+ out("attends").
+ where(neq("c")).
+ out("allocated").
+ where(eq("t")).
+ group().
+ by(select("s").by("name")).
+ by(group().by(select("t").by(valueMap("fromTime","toTime"))).
+ by(select("c").dedup().values("name").fold())).next()
+----
+
+[[appendix-d]]
+_In the "modern" graph, with a duplicate edge added, find the vertex pairs that have more than one edge between them._
+
+[gremlin-groovy,modern]
+----
+g.V(1).as("a").V(3).addE("created").property("weight",0.4d).from("a").iterate()
+g.V(1).outE("created")
+g.V().as("a").
+ out().as("b").
+ groupCount().
+ by(select("a","b")).
+ unfold().
+ filter(select(values).is(gt(1))).
+ select(keys)
+----
+
+[[appendix-e]]
+_In the "crew" graph, find vertices that match on a complete set of multi-properties._
+
+[gremlin-groovy,theCrew]
+----
+places = ["centreville","dulles"];[] // will not match as "purcellville" is missing
+g.V().not(has("location", without(places))).
+ where(values("location").is(within(places)).count().is(places.size())).
+ valueMap()
+places = ["centreville","dulles","purcellville"];[]
+g.V().not(has("location", without(places))).
+ where(values("location").is(within(places)).count().is(places.size())).
+ valueMap()
+----
+
+[[appendix-f]]
+_Methods for performing some basic mathematical operations in the "modern" graph._
+
+[gremlin-groovy,modern]
+----
+g.V().values("age").sum() // sum all ages
+g.V().values("age").fold(1, mult) // multiply all ages
+g.V().values("age").map(union(identity(), constant(-1)).sum()) // subtract 1
+g.V().values("age").map(union(identity(), identity()).sum()) // multiply by 2 (simple)
+g.V().values("age").map(union(identity(), constant(2)).fold(1, mult)) // multiply by 2 (generally useful for multiplications by n):
+----
+
+[[appendix-g]]
+_Dropping a vertex, as well as the vertices related to that dropped vertex that are connected by a "knows" edge in the
+"modern" graph_
+
+[gremlin-groovy,modern]
+----
+g.V().has('name','marko').outE()
+g.V().has('name','marko').sideEffect(out('knows').drop()).drop()
+g.V().has('name','marko')
+g.V(2,4,3)
+----
+
+[[appendix-h]]
+_For the specified graph, find all neighbor vertices connected to "A" as filtered by datetime, those neighbor vertices
+that don't have datetime vertices, and those neighbor vertices that have the label "dimon"._
+
+[gremlin-groovy]
+----
+g.addV().property("name", "A").as("a").
+ addV().property("name", "B").as("b").
+ addV().property("name", "C").as("c").
+ addV().property("name", "D").as("d").
+ addV().property("name", "E").as("e").
+ addV("dimon").property("name", "F").as("f").
+ addV().property("name", "G").as("g").property("date", 20160818).
+ addV().property("name", "H").as("h").property("date", 20160817).
+ addE("rel").from("a").to("b").
+ addE("rel").from("a").to("c").
+ addE("rel").from("a").to("d").
+ addE("rel").from("a").to("e").
+ addE("rel").from("c").to("f").
+ addE("occured_at").from("d").to("g").
+ addE("occured_at").from("e").to("h").iterate()
+// D and E have a valid datetime
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", gte(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// only E has a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", lte(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// only D has a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", gt(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+// neither D nor E have a valid date
+g.V().has("name", "A").out("rel").
+ union(where(out("occured_at").has("date", lt(20160817))),
+ __.not(outE("occured_at")).coalesce(out().hasLabel("dimon"), identity())).
+ valueMap()
+----
+
+[[appendix-i]]
+_Use element labels in a `select`._
+
+[gremlin-groovy,modern]
+----
+g.V(1).as("a").
+ both().
+ map(group().by(label).by(unfold())).as("b").
+ select("a","b").
+ map(union(project("a").by(select("a")), select("b")).
+ unfold().
+ group().
+ by(select(keys)).
+ by(select(values)))
+g.V().as("a").
+ both().
+ map(group().by(label).by(unfold())).as("b").
+ select("a","b").
+ group().
+ by(select("a")).
+ by(select("b").
+ group().
+ by(select(keys)).
+ by(select(values).fold())).
+ unfold().
+ map(union(select(keys).project("a").by(), select(values)).
+ unfold().
+ group().
+ by(select(keys).unfold()).
+ by(select(values).unfold().unfold().fold()))
+----
--- End diff --
Do we want to look good or perform good? You may have noticed it on the mailing list, I always try to prevent the use of `match()`. There were only a few questions that I ever answered with a match query and that was only for the sake of readability.
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by okram <gi...@git.apache.org>.
Github user okram commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95562174
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
--- End diff --
You should `href` to gremlin-users mailing list. https://groups.google.com/forum/#!forum/gremlin-users
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[GitHub] tinkerpop issue #531: Added more recipes
Posted by dkuppitz <gi...@git.apache.org>.
Github user dkuppitz commented on the issue:
https://github.com/apache/tinkerpop/pull/531
I went through all the code snippets again, optimized a few math examples and I think it's all looking good now.
VOTE: +1
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by spmallette <gi...@git.apache.org>.
Github user spmallette commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95640133
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
--- End diff --
I debated on whether to do that or not with recipes in general but given that I usually adapt the traversals to a narrative, alter the data or improve upon them from a performance perspective or usability perspective linking back doesn't always make sense, so rather than do it some of the times, I opted to not do it at all. The "appendix" might be different though....I don't recall if I made any modifications to those or just "copied" them writing my own explanation for what they were doing as a "title". Maybe adding the links for those would be useful in some way....let me think on that.
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by dkuppitz <gi...@git.apache.org>.
Github user dkuppitz commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95641135
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
--- End diff --
I believe what @okram meant is just one link, like:
> Many of the recipes are based on questions and answers provided on the [gremlin-users mailing list](https://groups.google.com/forum/#!forum/gremlin-users). This section...
Not a link to every discussion.
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[GitHub] tinkerpop pull request #531: Added more recipes
Posted by dkuppitz <gi...@git.apache.org>.
Github user dkuppitz commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/531#discussion_r95836475
--- Diff: docs/src/recipes/appendix.asciidoc ---
@@ -0,0 +1,226 @@
+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements. See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+////
+Appendix
+========
+
+Many of the recipes are based on questions and answers provided on the gremlin-users mailing list. This section
+contains a number of traversals from the mailing list that do not easily fit any particular pattern (i.e. a recipe),
+but are nonetheless interesting and thus remain good tools for learning Gremlin.
+
+[[appendix-a]]
+_For each person in a "follows" graph, determine the number of followers and list their names._
+
+[gremlin-groovy]
+----
+g.addV('name','marko').as('marko').
+ addV('name','josh').as('josh').
+ addV('name','daniel').as('daniel').
+ addV('name','matthias').as('matthias').
+ addE('follows').from('josh').to('marko').
+ addE('follows').from('matthias').to('josh').
+ addE('follows').from('daniel').to('josh').
+ addE('follows').from('daniel').to('marko').iterate()
+g.V().as('p').
+ map(__.in('follows').values('name').fold()).
+ group().by(select('p').by('name')).
+ by(project('numFollowers','followers').
+ by(count(local)).by()).next()
+----
+
+[[appendix-b]]
+_In the "modern" graph, show each person, the software they worked on and the co-worker count for the software and
+the names of those co-workers._
+
+[gremlin-groovy,modern]
+----
+g.V().hasLabel("person").as("p").
+ out("created").as("s").
+ map(__.in("created").
+ where(neq("p")).values("name").fold()).
+ group().by(select("p").by("name")).
+ by(group().by(select("s").by("name")).
+ by(project("numCoworkers","coworkers").
+ by(count(local)).by())).next()
+----
+
+[[appendix-c]]
+_Assuming a graph of students, classes and times, detect students who have a conflicting schedule._
+
+[gremlin-groovy]
+----
+g.addV(label, "student", "name", "Pete").as("s1").
+ addV(label, "student", "name", "Joe").as("s2").
+ addV(label, "class", "name", "Java's GC").as("c1").
+ addV(label, "class", "name", "FP Principles").as("c2").
+ addV(label, "class", "name", "Memory Management in C").as("c3").
+ addV(label, "class", "name", "Memory Management in C++").as("c4").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "10:00", "toTime", "11:00").as("t1").
+ addV(label, "timeslot", "date", "11/25/2016", "fromTime", "11:00", "toTime", "12:00").as("t2").
+ addE("attends").from("s1").to("c1").
+ addE("attends").from("s1").to("c2").
+ addE("attends").from("s1").to("c3").
+ addE("attends").from("s1").to("c4").
+ addE("attends").from("s2").to("c2").
+ addE("attends").from("s2").to("c3").
+ addE("allocated").from("c1").to("t1").
+ addE("allocated").from("c1").to("t2").
+ addE("allocated").from("c2").to("t1").
+ addE("allocated").from("c3").to("t2").
+ addE("allocated").from("c4").to("t2").iterate()
+g.V().hasLabel("student").as("s").
+ out("attends").as("c").
+ out("allocated").as("t").
+ select("s").
+ out("attends").
+ where(neq("c")).
+ out("allocated").
+ where(eq("t")).
+ group().
+ by(select("s").by("name")).
+ by(group().by(select("t").by(valueMap("fromTime","toTime"))).
+ by(select("c").dedup().values("name").fold())).next()
+----
+
+[[appendix-d]]
+_In the "modern" graph, with a duplicate edge added, find the vertex pairs that have more than one edge between them._
--- End diff --
Another way for undirected edges:
```
gremlin> g.V().where(without("x")).as("a").
......1> outE().as("e").inV().as("b").
......2> filter(bothE().where(neq("e")).otherV().where(eq("a"))).store("x").
......3> select("a","b").dedup()
==>[a:v[1],b:v[3]]
```
@okram I thought the following query should have the same result, but it doesn't (result is empty):
```
g.V().where(without("x")).as("a").
outE().as("e").inV().as("b").
where(bothE().where(neq("e")).otherV().as("a")).store("x").
select("a","b").dedup()
```
The difference is `filter(...where(eq("a")))` (works) vs. `where(....as("a"))` (doesn't work).
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