Gremlin CSV parse creating extra vertices - gremlin

Question

My code should read the 4 columns, split them into vertices for the first 2 columns, and edge properties for the last two columns.The CSV file has 33 unique vertices in 37 lines of data. What I don't understand is why I get 74 vertices instead and 37 edges. Interestingly enough, if I omit the addE statment I just get 37 vertices.
Obviously the property portion hasn't been included as I've been trying to resolve my current issues.
1\t2\tstep\tcmp
2\t3\tconductor\tna
3\t4\tswitch\tZ300
\t for tab
etc.
My code is:
graph = TinkerGraph.open()
graph.createIndex('myId', Vertex.class)
g = graph.traversal()
getOrCreate = { myid ->
p = g.V('myId', myid)
if (!p.hasNext())
{g.addV('connector').property('myId',myid) }
else
{p.next()}
}
new File('Continuity.txt').eachLine {
if (!it.startsWith("#")){
def row = it .split('\t')
def fromVertex = getOrCreate(row[0])
def toVertex = getOrCreate(row[1])
g.addE("connection").from(fromVertex).to(toVertex).iterate()
}
}

Answer 1

There's at least on problem in the code that I see. In this line:
p = g.V('myId', myid)
you are telling gremlin to find vertices with ids "myId" and whatever the value of the variable myid is. You instead want:
p = g.V().has('myId', myid)
The syntax you were using is from TinkerPop 2.x. I tested your code this way with some other changes and it seems to work properly now:
gremlin> graph = TinkerGraph.open()
==>tinkergraph[vertices:0 edges:0]
gremlin> graph.createIndex('myId', Vertex.class)
gremlin> g = graph.traversal()
==>graphtraversalsource[tinkergraph[vertices:0 edges:0], standard]
gremlin> getOrCreate = { myid ->
......1> if (!g.V().has('myId', myid).hasNext())
......2> g.addV('connector').property('myId',myid)
......3> else
......4> g.V().has('myId', myid)
......5> }
==>groovysh_evaluate$_run_closure1#29d37757
gremlin> g.addE('connection').from(getOrCreate(1)).to(getOrCreate(2)).iterate()
gremlin> g.addE('connection').from(getOrCreate(1)).to(getOrCreate(2)).iterate()
gremlin> g.V()
==>v[0]
==>v[2]
gremlin> g.E()
==>e[4][2-connection->0]
==>e[5][2-connection->0]