[R] linear regression by column

[Peter Ehlers]

On 2012-02-29 15:45, David Winsemius wrote:
>
> On Feb 29, 2012, at 6:39 PM, David Winsemius wrote:
>
>>
>> On Feb 29, 2012, at 1:53 PM, Filoche wrote:
>>
>>> Hi everyone.
>>>
>>> I have a DF with the first column being my independant variable and
>>> all
>>> other columns the dependent variables.
>>>
>>> Something like:
>>>
>>> x	y1	y2	y3
>>> ...	...	...	...
>>> ...	...	...	...
>>>
>>> What I'm trying to do is to perform a linear model for each of my
>>> "y". It is
>>> pretty simple with loops, but I'm trying to vectorize it using
>>> *apply*.
>>>
>>> For instance, I tried something like:
>>>
>>> apply(DF, 1, function(DF){lm(DF[,1] ~ Band1[,2:5])})
>>
>> apply( DF[2:5], 2, function(x){lm(DF[,1] ~ x)})
>>
>> You need to use the variable name that you created in the function
>> call and loop over columns, not rows.
>
> I read the request wrong. It would be:
>
> apply( DF[2:5], 2, function(y){y ~ DF$x)})

Another possibility: from ?lm:

"If response is a matrix a linear model is fitted separately by
  least-squares to each column of the matrix."

Peter Ehlers

>
>
>>
>>>
>>> But apparently it does not work.
>>
>> For about four or five reasons.
>>
>>> .
>>
>> David Winsemius, MD
>> West Hartford, CT
>>
>> ______________________________________________
>> 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.
>
> David Winsemius, MD
> West Hartford, CT
>
> ______________________________________________
> 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.