[R] Two Noobie questions

[Simon Pickett]

Allen,

I would suggest reading about the str() function. It's great for getting 
"inside" model outputs and seeing how they are constructed so you can 
extract all the specific calculations you want.

Its a bit fiddly to get used to but there are plenty of examples on this 
forum.

Hope this helps.

Simon.


----- Original Message ----- 
From: "AllenL" <allen.larocque at gmail.com>
To: <r-help at r-project.org>
Sent: Tuesday, January 06, 2009 7:47 PM
Subject: Re: [R] Two Noobie questions


>
> Thanks for your help!
>
> I combined the above two to get the following, which seems to work (if
> somewhat inelegant):
>
> int.List<-unlist(lapply(lmList, function(x) {coef(x)[1]}),use.names=FALSE)
> lmList is my list of lm objects.
> -Allen
>
>
>
>
>
> David Winsemius wrote:
>>
>>
>> On Jan 6, 2009, at 1:50 PM, AllenL wrote:
>>
>>>
>>> 1. I have a list of lm (linear model) objects. Is it possible to
>>> select,
>>> through subscripts, a particular element (say, the intercept) from
>>> all the
>>> models? I've tried something like this:
>>
>> ?coef
>> if your list of models is ml, then perhaps something like this
>> partially tested idea:
>>
>> lapply(ml, function(x) coef(x)[1] )
>>
>> This is what I get using that formulation an available logistic model:
>>
>>  > coef(lr.TC_HDL_BMI)[1]
>> Intercept
>> -6.132448
>>
>>
>>>
>>>
>>> List[[1:length(list)]][1]
>>> All members of the list are similar. My goal is to have a list of the
>>> intercepts and lists of other estimated parameters. Is it better to
>>> convert
>>> to a matrix? How to do this?
>>>
>>> 2. Connected to this, how do I convert from a list back to a vector?
>>> This
>>> problem arose from using "split" to split a vector by a factor, then
>>> selecting a subset of this (ie. length>10), leaving me with subset
>>> list of
>>> my original. Unsplit(newList, factor) doesn't work, presumably due
>>> to my
>>> removal of some values. Thoughts?
>>
>> ?unlist
>>
>>  > ll <- list(1,2,3,4)
>>  > ll
>> [[1]]
>> [1] 1
>>
>> [[2]]
>> [1] 2
>>
>> [[3]]
>> [1] 3
>>
>> [[4]]
>> [1] 4
>>
>>  > unlist(ll)
>> [1] 1 2 3 4
>>  > str(unlist(ll))
>>   num [1:4] 1 2 3 4
>>  > is.vector(unlist(ll))
>> [1] TRUE
>>
>> -- 
>> David Winsemius
>>>
>>>
>>> Thanks!
>>> -Allen
>>>
>>>
>>>
>>> -- 
>>> View this message in context:
>>> http://www.nabble.com/Two-Noobie-questions-tp21316554p21316554.html
>>> Sent from the R help mailing list archive at Nabble.com.
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
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>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>
> -- 
> View this message in context: 
> http://www.nabble.com/Two-Noobie-questions-tp21316554p21317630.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>