Message-ID: <ACE465E1-1207-432A-B253-B394701473A6@comcast.net>
Date: 2009-11-13T11:41:51Z
From: David Winsemius
Subject: processing log file
In-Reply-To: <313692.68426.qm@web28505.mail.ukl.yahoo.com>
On Nov 13, 2009, at 6:03 AM, Jabez Wilson wrote:
> Dear all, I'm trying to process a log file which logs the date, the
> username and the computer number accessed. The table looks like this:
>> table.users
> Date UserName Machine
> 1 2008-11-25 John 641
> 2 2008-11-25 Clive 611
> 3 2008-11-25 Jeremy 641
> 4 2008-11-25 Walt 722
> 5 2008-11-25 Tony 645
> 6 2008-11-26 Tony 645
> 7 2008-11-26 Tony 641
> 8 2008-11-26 Tony 641
> 9 2008-11-26 Walt 641
> 10 2008-11-26 Walt 645
> 11 2008-11-30 John 641
> 12 2008-11-30 Clive 611
> 13 2008-11-30 Tony 641
> 14 2008-11-30 John 641
> 15 2008-11-30 John 641
> ..................etc
> 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.
> In the above example, therefore on 2008-11-25 there were 5 separate
> users accessing 4 machines, on 2008-11-26 there were 2 unique users
> who used 2 machines (although both logged on more than once).
> I've got as far as apply(table.users, 2, FUN=table) which gives me
> an output of date, or username or machine and how many times they
> were accessed, but not really what I want.
> Any help appreciated
You were almost there. Just use lapply on the list object you produced:
> lapply(apply(table.users, 2, FUN=table), length)
$Date
[1] 3
$UserName
[1] 5
$Machine
[1] 4
Or if you want the individual items that you requested:
> lapply(apply(table.users, 2, FUN=table), length)$UserName
[1] 5
> lapply(apply(table.users, 2, FUN=table), length)$Machine
[1] 4
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT