repeated searching of no-missing values

graphics,statistical analysis etc. as well as programming. There are just
too many possible data structures to expect logical consistency in their
handling throughout (if one can even define what that means in specific
instances!).

I disagree with this claim: I think it is possible to create a logical
and consistent set of functions for working with the all basic data
structures in R, and this is what I have attempted to do with my plyr
package.  Any remaining inconsistencies are due to my failings, not
the fundamental difficulty of the task.

Hadley

http://had.co.nz/