[R] Question re: interpolation

[Jessica Schedlbauer]

Hello,

I have a matrix in which two variables, x and y, are used together to determine z.  The variables x and y are sorted into classes.  Specifically, values for variable x range from 0 to 2.7 and are sorted into class increments of 0.15 and variable y ranges from 0-2100 with class increments of 100.  For each x-y class combination, I have calculated a mean value of z from existing data.  However there are gaps in the existing data (i.e., x-y combinations for which there are no z data).  I would like to interpolate values to fill in these missing datapoints, but have so far been unable to find a straightforward way of doing so in R.  There are many gaps in the data and I need to repeat this process for several individual datasets.  That said, I am looking for a way to avoid interpolating each missing point separately.

Any suggestions would be greatly appreciated.

Regards,
Jessica Schedlbauer