[R] Two Noobie questions

Neil Beddoe Neil.Beddoe at mbamfunds.com
Thu Jan 8 08:47:11 CET 2009


You can also use subscripts to get at things with a bit of playing around.

> summary(lm(x~seq(1,length(x),1)))

Call:
lm(formula = x ~ seq(1, length(x), 1))

Residuals:
     Min       1Q   Median       3Q      Max 
-40.0961 -15.5289  -0.6489  12.7488  41.0107 

Coefficients:
                       Estimate Std. Error t value Pr(>|t|)    
(Intercept)          165.259602   1.620906 101.955   <2e-16 ***
seq(1, length(x), 1)  -0.048711   0.005551  -8.775   <2e-16 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 

Residual standard error: 18.19 on 503 degrees of freedom
Multiple R-squared: 0.1328,     Adjusted R-squared: 0.131 
F-statistic:    77 on 1 and 503 DF,  p-value: < 2.2e-16 

> summary(lm(x~seq(1,length(x),1)))[[4]][[4]]
[1] 0.005551145
> summary(lm(x~seq(1,length(x),1)))[[4]][[2]]
[1] -0.04871091
> 

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of AllenL
Sent: 06 January 2009 19:48
To: r-help at r-project.org
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
>> 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.
> 
> ______________________________________________
> 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.
> 
> 

-- 
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