[R] reference text variables as column name to plot

[Bert Gunter]

May I suggest that "DYDD" -- Do Your Due Dilgence -- might be an
appropriate reply to this sort of query. A purposefully less crude and
more polite version of "RTFM."

-- Bert

On Tue, Nov 30, 2010 at 8:51 AM, jim holtman <jholtman at gmail.com> wrote:
> Where is the "column"?  Is it in a matrix/dataframe?  Why are you
> trying to plot 12 points against 'z' which has 24 values?  You can
> reference the column by:
>
> plot(yourDF[, s])
>
> where 's' is what you created as the column name.  Need to refer to
> indexing in the Intro to R.
>
> On Tue, Nov 30, 2010 at 11:40 AM, Graves, Gregory <ggraves at sfwmd.gov> wrote:
>> Having given myself carpal tunnel looking for answer to this ...
>>
>>
>>
>> I have a dataset each column of which has 12 rows in it.  I created a
>> variable 'z' as follows:
>>
>>
>>
>> z=1:24
>>
>>
>>
>> Since I have a large number of these plots to make, and they are a bit
>> complex, I want to want to reference the column I want to plot via a
>> variable containing the name of that column.  As follows:
>>
>>
>>
>> similar='1978'
>>
>> s=paste('Y',similar,sep='')
>>
>>
>>
>> variable s now contains 'Y1978' which is the name of one of the columns.
>>
>>
>>
>> However, when I try to plot
>>
>>
>>
>> plot(z,s,type='l')
>>
>>
>>
>> I get a 'x and y lengths differ' error because variable s is being
>> recognized as 'Y1978' length=1, rather than the contents of the column
>> Y1978 length=12.
>>
>>
>>
>> I tried all the usual tricks I know like &s.  How do you get R to
>> reference a variable as a column name?
>>
>>
>>
>> Thank you.
>>
>>
>>
>> Gregory A. Graves, Lead Scientist
>>
>> Everglades REstoration COoordination and VERification (RECOVER)
>>
>> Restoration Sciences Department
>>
>> South Florida Water Management District
>>
>> Phones:  DESK: 561 / 682 - 2429
>>
>>                   CELL:  561 / 719 - 8157
>>
>>
>>
>>
>>        [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> 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?
>
> ______________________________________________
> 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.
>



-- 
Bert Gunter
Genentech Nonclinical Biostatistics