Sorry. Since . is commonly used but a matrix LHS less so I assumed you were
asking about the matrix part.
Dot means everything not on the LHS of the formula.


On Sun, Nov 29, 2009 at 12:18 PM, Carl Witthoft <carl@witthoft.com> wrote:

> As others helpfully pointed out, the meaning of "." in a formula is
> provided in the Details section of ?formula.  (But NOT in ?lm)
>
> Ista Zahn wrote:
>
>> The help page for lm says:
>>
>> "If ‘response’ is a matrix a linear model is fitted separately by
>>     least-squares to each column of the matrix."
>>
>> -Ista
>>
>>
>> On Sun, Nov 29, 2009 at 11:46 AM, Carl Witthoft <carl@witthoft.com>
>> wrote:
>>
>>> Hi,
>>> A recent thread provided a (working) construct for lm:
>>>
>>> lm(as.matrix(freeny[ix]) ~., freeny[-ix])
>>>
>>>
>>> Can someone explain what is meant by the formula in that expression,
>>> that is,  what does "mymatrix~."  do?  I couldn't find any such example
>>> in
>>> the lm() or formula() help pages.
>>>
>>> thanks
>>> Carl
>>>
>>> ______________________________________________
>>> R-help@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@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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