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 was thinking of using by() again, but I can't figure out how to write it properly. Any ideas? Thanks a lot, Xavier
model fitting using by(): how to get fitted values?
2 messages · xavier.chardon at free.fr, Duncan Murdoch
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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