All graph data entries must have a x and y coordinates.
It would be more sensible to determine a default order
for these in the data so as to avoid the typing of
x=1,y=2 at every single data.(list|file) call.
Just as users (e.g. me) of a cmd line plotting routine
expect to call
$ bozoplot results.dat
with two columns entries:
1 3 etc
and have a graph plotting these as x, y. Users (e.g. I)
would expect to be able to call pyx.graph.graphxy.data.
methods without having to specify at every call which
is column x and which is y.