How do I collect values from a vertex used in a traversal? - gremlin

Question

I want the details of a vertex along with details of vertices that are joined to it.
I have a group vertex, incoming 'member' edges to user vertices. I want the details of the vertices.
g.V(1).as('a').in('member').valueMap().as('b').select('a','b').unfold().dedup()
==>a=v[1]
==>b={image=[images/profile/friend9.jpg], name=[Thomas Thompson], email=[me#thomasthompson.co.uk]}
==>b={image=[images/profile/friend13.jpg], name=[Laura Tostevin], email=[me#lauratostevin.co.uk]}
==>b={image=[images/profile/friend5.jpg], name=[Alan Thompson], email=[me#alanthompson.co.uk]}
==>b={image=[images/profile/friend10.jpg], name=[Laura Bourne], email=[me#laurabourne.co.uk]}
Ideally what I'd want is:
{label: 'group', id=1, name='A Group', users=[{id=2, label="user",name=".."}, ... }]}
When I tried a project, it didn't like me using 'in'
gremlin> g.V('1').project('name','users').by('name').by(in('member').select())
groovysh_parse: 1: unexpected token: in # line 1, column 83.
'name','users').by('name').by(in('member

Answer 1

To get your preferred output format, you have to join the group's valueMap() with the list of users. On TinkerPop's modern toy graph you would do something like this:
gremlin> g.V(3).union(valueMap(true).
by(unfold()),
project('users').
by(__.in('created').
valueMap(true).
by(unfold()).
fold())).
unfold().
group().
by(keys).
by(select(values))
==>[name:lop,id:3,lang:java,label:software,users:[[id:1,label:person,name:marko,...],...]]
Mapping this to your graph should be pretty straight-forward, it's basically just about changing labels.

Answer 2

Because in is a reserved keyword in Groovy you must use the verbose syntax __.in
try:
g.V('1').project('name','users').by('name').by(__.in('member').valueMap(true).fold())