[R] extract data for specific levels factor

[Sarah Goslee]

On Tue, Oct 25, 2011 at 4:49 PM, Nordlund, Dan (DSHS/RDA)
<NordlDJ at dshs.wa.gov> wrote:
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of Sarah Goslee
>> Sent: Tuesday, October 25, 2011 12:50 PM
>> To: Andrés Aragón
>> Cc: R-help at r-project.org
>> Subject: Re: [R] extract data for specific levels factor
>>
>> Hi,
>>
>> 2011/10/25 Andrés Aragón <armandres at gmail.com>:
>> > Dear all,
>> >
>> > I'm trying to analyze data with the following structure:
>> >
>> > ind          cat            tx      age
>> > 40.2 por fol peq     vh        35
>> > 41.9 por fol med     vh        35
>> > 68.9 por fol preov   vh       35
>> > 71.5 por fol peq      ser       37
>> > 67.5  por fol med    ser       37
>> > 76.9  por fol preov   ser     37
>> > 78.7  por fol peq      otr      37
>> > 78.3  por fol med    otr       37
>> > 82.1  por fol preov   otr      37
>> > 83.9  por fol peq      vh       37
>> > 80.6  por fol med      vh      37
>> > 76.1  por fol preov     vh     37
>> > 86.9  por fol peq        ser     35
>> > 97.7  por fol med       ser     35
>> > 62.3  por fol preov     ser     35
>> >
>> >
>> >
>> > I want to separate exclusively some of factor levels  (“por fol peq”
>> > in the “cat” colum). I am using ggplot2  and I only can plot all of
>> > factors, not separately. I did try ddply without success.
>> > Any help is welcome.
>>
>> This kind of question is *so* much easier to answer if you provide
>> reproducible data with dput(). This is untested because of lack of
>> data, but what about
>>
>> newdata <- origdata[origdata$cat %in% c("por", "fol", "peq"),]
>>
>> Depending on the effect you want, you may also wish to drop the
>> unused levels or reorder the levels using factor().
>>
>> Sarah
>>
>
> Or, if I have guessed correctly, something like this will work
>
> newdata<- origdata[origdata$cat == 'por fol peq',]

I think you're right, Dan - I misinterpreted the data. Another
argument for dput()!

-- 
Sarah Goslee
http://www.functionaldiversity.org