[R] data file with columns of unequal length

[William Simpson]

I am running an expt that presents a point process input x and
measures a point process output y. The times of each event are
recorded. The lengths of the data records of x and y are necessarily
different, and can be different by a factor of 10. I would like to
save these data after each experiment as a file with two columns, one
for x and one for y.

However, R dataframes require columns of equal length. One solution is
to fill the "empty" places in y with NAs so it has the same length as
x. I view that as unsatisfactory (there are in reality no missing
values). Another possibility is to store x and y in separate files. I
also view that as unsatisfactory (it is too easy to lose track of the
y file corresponding to a given x file).

Can anyone suggest a way to deal with this situation?

Thanks very much for any help.

Bill