No need for an XY graph in this case; just wire the array to a graph
and if you want to zoom in on something programmatically you can
control the min and max, scaling and pretty much everything else using
a property node (just right-click on the graph, select create property
node and then click on it to select which property to set, you can
expand it to read/write multiple properties with the same node, or
create multiple property nodes. The Y axis will by default just show
the array index number unless you set the X0 and delta X properties.