[R] Transforming a string to a variable's name? help me newbie...

[tsunhin wong]

I want to combine all dataframes into one large list too...
But each dataframe is a 35 columns x varying number of rows structure
(from 2000 to >9000 rows)
I have ~1500 dataframes of these to process, and that add up to >
1.5Gb of data...

Combining dataframes into a single one require me to transform each
single dataframe into one line, but I really don't have a good
solution for the varying number of rows scenario... And also, I don't
want to stall my laptop every time I run the data set: maybe I can do
that when my prof give me a ~ 4Gb ram desktop to run the script ;)

Thanks! :)

- John

On Mon, Dec 8, 2008 at 1:36 PM, Greg Snow <Greg.Snow at imail.org> wrote:
> In the long run it will probably make your life much easier to read all the dataframes into one large list (and have the names of the elements be what your currently name the dataframes), then you can just use regular list indexing (using [[]] rather than $ in most cases) instead of having to worry about get and assign and the risks/subtleties involved in using those.
>
> Hope this helps,
>
> --
> Gregory (Greg) L. Snow Ph.D.
> Statistical Data Center
> Intermountain Healthcare
> greg.snow at imail.org
> 801.408.8111
>
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of tsunhin wong
>> Sent: Monday, December 08, 2008 8:45 AM
>> To: Jim Holtman
>> Cc: r-help at r-project.org
>> Subject: Re: [R] Transforming a string to a variable's name? help me
>> newbie...
>>
>> Thanks Jim and All!
>>
>> It works:
>> tmptrial <- trialcompute(trialextract(
>> get(paste("t",tmptrialinfo[1,2],tmptrialinfo[1,16],".gz",sep="")) ,
>> tmptrialinfo[1,32],secs,sdm),secs,binsize)
>>
>> Can I use "assign" instead? How should it be coded then?
>>
>> Thanks!
>>
>> - John
>>
>> On Mon, Dec 8, 2008 at 10:40 AM, Jim Holtman <jholtman at gmail.com>
>> wrote:
>> > ?get
>> >
>> >
>> > Sent from my iPhone
>> >
>> > On Dec 8, 2008, at 7:11, "tsunhin wong" <thjwong at gmail.com> wrote:
>> >
>> >> Dear all,
>> >>
>> >> I'm a newbie in R.
>> >> I have a 45x2x2x8 design.
>> >> A dataframe stores the metadata of trials. And each trial has its
>> own
>> >> data file: I used "read.table" to import every trial into R as a
>> >> dataframe (variable).
>> >>
>> >> Now I dynamically ask R to retrieve trials that fit certain
>> selection
>> >> criteria, so I use "subset", e.g.
>> >> tmptrialinfo <- subset(trialinfo, (Subject==24 &
>> Filename=="v2msa8"))
>> >>
>> >> The name of the dataframe / variable of an individual trial can be
>> >> obtained using:
>> >> paste("t",tmptrialinfo[1,2],tmptrialinfo[1,16],".gz",sep="")
>> >> Then I get a string:
>> >> "t24v2msa8.gz"
>> >> which is of the exact same name of the dataframe / variable of that
>> >> trial, which is:
>> >> t24v2msa8.gz
>> >>
>> >> Can somebody tell me how can I change that string (obtained from
>> >> "paste()" above) to be a usable / manipulable variable name, so that
>> I
>> >> can do something, such as:
>> >> (1)
>> >> tmptrial <- trialcompute(trialextract(
>> >> paste("t",tmptrialinfo[1,2],tmptrialinfo[1,16],".gz",sep="")
>> >> ,tmptrialinfo[1,32],secs,sdm),secs,binsize)
>> >> instead of hardcoding:
>> >> (2)
>> >> tmptrial <-
>> >>
>> trialcompute(trialextract(t24v2msa8.gz,tmptrialinfo[1,32],secs,sdm),sec
>> s,binsize)
>> >>
>> >> Currently, 1) doesn't work...
>> >>
>> >> Thanks in advance for your help!
>> >>
>> >> Regards,
>> >>
>> >>     John
>> >>
>> >> ______________________________________________
>> >> 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.
>