Recursively query simpler tree-like structures with Gremlin

Question

Consider the following data:

g.addV(\'RootTopic\').property(\'name\', \'A\').as(\'A\')
.addV(\'RootTopic\').property(\'name\', \'M\').as(\'M\')
.addV(\'Topic\').         


        

Answer 1

The by() modulator can take more than just a property key value as an argument. You can also pass in an anonymous traversal which would thus allow:

g.V().hasLabel('RootTopic').
  repeat(out()).times(2).
    emit().
  tree()
    by(values('name','k1','k2').fold())

or you might use project() if you had more complex output:

g.V().hasLabel('RootTopic').
  repeat(out()).times(2).
    emit().
  tree()
    by(project('name','k1','degree').
         by('name').
         by('k1').
         by(both().count())

The main point to take away here is that with an anonymous traversal you can develop just about any output you would like.