[R] processing log file

[Karl Ove Hufthammer]

On Fri, 13 Nov 2009 11:03:31 +0000 (GMT) Jabez Wilson 
<jabezwuk at yahoo.co.uk> wrote:
> What I want to do is to find out how many unique users logged 
> on each day, and how many individual machines where accessed per day.

Use the 'plyr' package:

library(plyr)
ddply(table.users, .(Date), summarise,
  users=length(unique(Username)),
  machines=length(unique(Machine)))

-- 
Karl Ove Hufthammer