R-Notes

Rescuing the debian dpkg system http://www.linuxworld.com/story/32607.htm

aggregate (equivalent to collapse in Stata).
Use length to get frequencies, sum, mean, var, sd, etc. as expected.

To get access to the "slots" of a class (which is roughly equivalent to the parts of an object), use "@" for example

mymle@vcov, which shows the variance covariance matrix
mymle@details, which shows the list returned from optim

In particular mymle@details$hessian shows the part (hessian) of the object returned by optim.