Message-ID: <4A01828D.6080400@stats.uwo.ca>
Date: 2009-05-06T12:29:01Z
From: Duncan Murdoch
Subject: model fitting using by(): how to get fitted values?
In-Reply-To: <2110151104.4193991241612533094.JavaMail.root@spooler8-g27.priv.proxad.net>
On 06/05/2009 8:22 AM, xavier.chardon at free.fr wrote:
> Hi all,
>
> I'm doing nonlinear regressions on data with several factors. I want to fit say a logistic curve with different parameter values for each factor level. So I'm doing something like:
>
> tmp <- by( myData, list(myFactor1, myFactor2), function(x) nls(...) )
>
> It works fine. However, I could not find an easy way to retrieve fitted values. I can use fitted() on each element of tmp, but that gives me as many vectors as there are combinations of factor levels.
I think lapply() (or maybe sapply) will do what you want. I haven't
tried this, but it should be something like
lapply(tmp, fitted)
Duncan Murdoch
>
> I was thinking of using by() again, but I can't figure out how to write it properly.
>
> Any ideas?
>
>
> Thanks a lot,
>
> Xavier
>
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