Thanks a lot for the quick replies.
But, doesn't "tapply" or "aggregate" provide a matrix format rather
than data frame format?
On 3/14/07, Rich@mango-solutions.com <Rich@mango-solutions.com> wrote:
Sorry ...
I mean "aggregate(df$value, df[,1:3], mean)"
Rich.
mangosolutions
-----Original Message-----
From: Rich@Mango-Solutions.com [mailto:Rich@Mango-Solutions.com]
Sent: 14 March 2007 21:14
To: 'Wensui Liu'; 'Neung-Hwan Oh'
Cc: s-news@wubios.wustl.edu
Subject: Re: [S] group by
Yes ... you can use tapply in S. For the structure you're using, I'd
probably recommend "aggregate" though ...
Something like "aggregate(df[,1:3], df$value, mean)"
Rich.
mangosolutions
-----Original Message-----
From: Wensui Liu [mailto:liuwensui@gmail.com]
Sent: 14 March 2007 21:02
To: Neung-Hwan Oh
Cc: s-news@wubios.wustl.edu
Subject: Re: [S] group by
I am not sure if in Splus, there is a nice function like tapply() in R or
not.
On 3/14/07, Neung-Hwan Oh <ultisol@gmail.com> wrote:
> Hello,
>
> How can you calculate the following example in s-plus? In Access, it is
> relatively easy with "Group By" and I am wondering whether there is a
> similar function that I missed in S-Plus.
>
>
>
> "From this table"
>
> site.no date time value
>
> 1 1989/04/27 12:00 1.0
>
> 2 1975/10/01 19:00 2.0
>
> 2 1975/10/01 20:00 4.0
>
> 3 1993/04/10 09:00 3.0
>
> 3 1993/04/10 12:00 6.0
>
> 3 1993/04/10 15:00 9.0
>
>
>
> "To this (averages per date per site)" + (count column?)
>
> 1 1989/04/27 12:00 1.0 (1.0)
>
> 2 1975/10/01 19:30 3.0 (2.0)
>
> 3 1993/04/10 12:00 6.0 (3.0)
>
>
>
> Many thanks!
>
> NH
--
WenSui Liu
A lousy statistician who happens to know a little programming
(http://spaces.msn.com/statcompute/blog)
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