[R] Adding variables

[David Winsemius]

Well, I had never seen any help pages use "attenu" as an example. Like  
Jim I assumed that you were offering code that was operating on some  
private copy of data, If you look at the number of datasets, I think  
it unreasonable to expect the great majority of potentially helpful  
persons to know all of them either.

So why were you trying to add a factor variable to a numeric, anyway?  
If your hope was to convert those codes to numeric then it's a FAQ:

http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-do-I-convert-factors-to-numeric_003f

If the problem were more basic, and you did not know what was in that  
dataset then the answer might have bee:

str(attenu)

-- 
David




On Sep 27, 2009, at 7:47 AM, tzygmund mcfarlane wrote:

> Jim,
>
> Both my emails contained reproducible code (the first one wasn't
> completely reproducible - it required one to know that "attenu" is a
> base R dataset).
>
> Anyway, thanks for your help.
>
> On Sat, Sep 26, 2009 at 8:11 PM, jim holtman <jholtman at gmail.com>  
> wrote:
>> I assumed (since you did not provide reproducible code) that 'mag'  
>> was
>> a matrix.  If 'station' is a matrix, then
>>
>> mag + rowSums(station)
>>
>> will work.  If that does not work, then you need to tell us what your
>> data objects are.
>>
>> On Sat, Sep 26, 2009 at 11:39 AM, tzygmund mcfarlane
>> <tzygmund at googlemail.com> wrote:
>>> Hi Jim,
>>>
>>> I might be missing something but your command gives the error:
>>> Error in rowSums(mag) : 'x' must be an array of at least two  
>>> dimensions
>>>
>>> #############################
>>> data(attenu)
>>> attach(attenu)
>>> rowSums(mag) + rowSums(station)
>>> attenu$new<-rowSums(cbind(mag, station))
>>> #############################
>>>
>>> Thanks
>>>
>>>
>>> On Sat, Sep 26, 2009 at 4:30 PM, jim holtman <jholtman at gmail.com>  
>>> wrote:
>>>> Probably more efficient if you remove the 'cbind' which would  
>>>> create a
>>>> combined matrix.  Use the following:
>>>>
>>>> rowSums(mag) + rowSums(station)
>>>>
>>>> On Sat, Sep 26, 2009 at 11:16 AM, tzygmund mcfarlane
>>>> <tzygmund at googlemail.com> wrote:
>>>>> Hi,
>>>>>
>>>>> For very large matrices, is this the most efficient way to add two
>>>>> variables together?
>>>>>
>>>>> #############################
>>>>> attach(attenu)
>>>>> new<-rowSums(cbind(mag, station))
>>>>> #############################
>>>>>
>>>>> Also, could I be directed to some resources for working with very
>>>>> large datasets?
>>>>>
>>>>> Thanks
>>>>>
>>>>> ______________________________________________
>>>>> 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.
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Jim Holtman
>>>> Cincinnati, OH
>>>> +1 513 646 9390
>>>>
>>>> What is the problem that you are trying to solve?
>>>>
>>>
>>
>>
>>
>> --
>> Jim Holtman
>> Cincinnati, OH
>> +1 513 646 9390
>>
>> What is the problem that you are trying to solve?
>>
>
> ______________________________________________
> 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