Add different values to each of multiple vertices - gremlin

Question

I know that I can select multiple specific vertices by id in a single step, for example (using gremlin-python syntax):
g.V([1, 2, 3]).next()
>>> [v[1], v[2], v[3]]
How can I then add a property with different values to each of these selected items? For example, I would like that:
Vertex 1 has property 'x' with value 'a'
Vertex 2 has property 'x' with value 'b'
Vertex 3 has property 'x' with value 'c'
So I'd like to be able to say something like:
g.V([1, 2, 3]).<add property 'x' with values ['a', 'b', 'c']>.next()
Is it possible?

Answer 1

You could use choose() to accomplish something like that which will give you if-then-else type branching. Using the modern toy graph that ships with TinkerPop distributions:
gremlin> g.V(1,2,3).
......1> choose(id()).
......2> option(1, property('switch','a')).
......3> option(2, property('switch','b')).
......4> option(3, property('switch','c')).iterate()
gremlin> g.V(1,2,3).
......1> project('id','switch').
......2> by(id).
......3> by('switch')
==>[id:1,switch:a]
==>[id:2,switch:b]
==>[id:3,switch:c]
As of TinkerPop 3.3.3, you could also do something like this which uses a side-effect:
gremlin> g.withSideEffect('x',[1:'a',2:'b',3:'c']).
......1> V(1,2,3).as('v').
......2> property('switch', select('x').
......3> select(select('v').id()))
==>v[1]
==>v[2]
==>v[3]
gremlin> g.V(1,2,3).
......1> project('id','switch').
......2> by(id).
......3> by('switch')
==>[id:1,switch:a]
==>[id:2,switch:b]
==>[id:3,switch:c]
You need 3.3.3+ because you need the ability to select() runtime generated keys which was only added in that version.
I don't think you can use the key of the Map of "x" to handle the lookup of the vertex without a lambda (maybe i'm not thinking of something simple), so unfortunately you have to specify the ids twice, but you could parameterize that pretty easily because you just need to construct the Map and then grab the .keys() from it to give to V().