Message-ID: <240A0FF472D2D3499BD041AA1FAF9B8651DBAC@EXCHVS02.ad.sfwmd.gov>
Date: 2010-12-01T12:13:16Z
From: Graves, Gregory
Subject: reference text variables as column name to plot [SOLVED]
In-Reply-To: <3DFD569A-A648-4157-B164-BFD05089F684@comcast.net>
The following works nicely. Thank you.
plot(z, sf[[s]], type="l") #where the dataframe name in my case is "sf"
Sorry - I meant to say there were 24 rows in each column, so z=1:24
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
-----Original Message-----
From: David Winsemius [mailto:dwinsemius at comcast.net]
Sent: Tuesday, November 30, 2010 11:50 AM
To: Graves, Gregory
Cc: r-help at r-project.org
Subject: Re: [R] reference text variables as column name to plot
On Nov 30, 2010, at 11:40 AM, Graves, Gregory wrote:
> Having given myself carpal tunnel looking for answer to this ...
>
>
>
> I have a dataset
Named.... what?
> each column of which has 12 rows in it. I created a
> variable 'z' as follows:
>
>
>
> z=1:24 s
Why did you put twice as many elements in z as there are in a column?
>
>
>
> 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')
Try this ... assuming that there really are 12 item length columns in
a dataframe named, dfm.
plot(1:12, dfm[[s]], type="l")
dataframes are lists that can be accessed by the names of columns
which are interpreted. Don't assume that you can get such
interpretation with the $ operator.
>
>
>
> 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.
Huh? "&" is a logical operator.
> 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.
David Winsemius, MD
West Hartford, CT