[R] How to refer the element in a named list?

[Peng Yu]

On Sun, Sep 6, 2009 at 12:45 PM, David Winsemius<dwinsemius at comcast.net> wrote:
>
> On Sep 6, 2009, at 1:35 PM, Duncan Murdoch wrote:
>
>> On 06/09/2009 1:04 PM, Peng Yu wrote:
>>>
>>> Hi,
>>> I thought that 'coefficients' is a named list, but I can not refer to
>>> its element by something like r$coefficients$y. I used str() to check
>>> r. It says the following. Can somebody let me know what it means?
>>
>> The line that matters is the one
>>
>> $ coefficients : Named num [1:2] 1.12e-15 1.00
>>
>> It says that coefficients is a numeric ("num") vector, not a list.  So
>> r$coefficients["y"] will extract the y coefficient.
>>
>
> And r$coefficients[`(Intercept)`] # note back-quote, should get you the
> intercept

Back-quotes do not work.

> r$coefficients[`(Intercept)`]
Error: object '(Intercept)' not found
> r$coefficients["(Intercept)"]
 (Intercept)
1.123467e-15


> ?coef
>
> Generally coef(fit) will extract model coefficients across a wider range of
> R model objects.
>
>
>> Duncan Murdoch
>>
>>
>>>  ..- attr(*, "names")= chr [1:2] "(Intercept)" "y"
>>> $ Rscript lm.R
>>>>
>>>> x=1:10
>>>> y=1:10
>>>> r=lm(x~y)
>>>> class(r)
>>>
>>> [1] "lm"
>>>>
>>>> mode(r)
>>>
>>> [1] "list"
>>>>
>>>> r
>>>
>>> Call:
>>> lm(formula = x ~ y)
>>> Coefficients:
>>> (Intercept)            y
>>>  1.123e-15    1.000e+00
>>>>
>>>> r$coefficients[1]
>>>
>>> (Intercept)
>>> 1.123467e-15
>>>>
>>>> r$coefficients[[1]]
>>>
>>> [1] 1.123467e-15
>>>>
>>>> r$coefficients[2]
>>>
>>> y
>>> 1
>>>>
>>>> r$coefficients[[2]]
>>>
>>> [1] 1
>>>>
>>>> str(r)
>>>
>>> List of 12
>>> $ coefficients : Named num [1:2] 1.12e-15 1.00
>>>  ..- attr(*, "names")= chr [1:2] "(Intercept)" "y"
>>> Regards,
>>> Peng
>>> ______________________________________________
>>> 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.
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
>