I don't see any plotting commands so I don't know what kind of plot you're trying to create.
The problem can likely be solved by indexing. Spend some time on that page. Indexing is one of the main features of matlab.
For example,
idx = abs(L) <= 1;
plot(q(idx),e(idx), 'ro')
hold on
plot(q(~idx),e(~idx), 'bo')