Hi Joshua

Many thanks.  

The values of flow can be accessed in a weird way and we can used them for some 
calculations.  Since I am a newbie as far as using R is concerned I wonder 
whether you could tell me how to create a structure in R that looks like the 
one I have in matlab (that is, a variable a that contains river1 and river2 
that contains flow and precipitation).

Cheers

Ed


-----Original Message-----
From: Joshua Wiley [mailto:jwiley.ps...@gmail.com] 
Sent: Sunday, March 13, 2011 7:20 PM
To: Eduardo M. A. M.Mendes
Cc: R-help@r-project.org
Subject: Re: [R] readMat - how to retrieve the variables

On Sun, Mar 13, 2011 at 2:56 PM, Eduardo M. A. M.Mendes <emammen...@gmail.com> 
wrote:
> Hi Joshua
>
> Many thanks for the prompt reply.
>
> I have saved a short version of the matlab file and the output on R is
>
>> b=readMat("testr.mat")
>> b
> $a
> , , 1
>
>       [,1]
> river1 List,2
> river2 List,2

It looks like you are dealing with a special series of lists nested within 
three dimensional arrays within lists.  My suggestion would be to double check 
that the matlab file has reasonable data (whatever that means) and try to 
double check your use of readmat (do you meet all the requirements for 
versions, etc.).  That is not a common R structure so the extraction is 
similarly uncommon.  Perhaps Henrik will be along with more helpful answers.

Good luck,

Josh
>
>
> attr(,"header")
> attr(,"header")$description
> [1] "MATLAB 5.0 MAT-file, Platform: PCWIN, Created on: Sun Mar 13 18:51:54 
> 2011                                                  "
>
> attr(,"header")$version
> [1] "5"
>
> attr(,"header")$endian
> [1] "little"
>
> When I issue the command b$a[,,1]$river1[,,1]$flow  I see the flow values.
>
> Unfortunately the data is confidential.
>
> Many thanks
>
> Ed
>
>
> -----Original Message-----
> From: Joshua Wiley [mailto:jwiley.ps...@gmail.com]
> Sent: Sunday, March 13, 2011 6:30 PM
> To: Eduardo M. A. M.Mendes
> Cc: R-help@r-project.org
> Subject: Re: [R] readMat - how to retrieve the variables
>
> Hi Ed,
>
> Can you please provide *at least* the R output from running:
>
> str(data)
>
> where "data" is the variable name you stored the results of readMat() in.  If 
> it is reasonably small and can be sent as plaintext (I do not know Matlabs 
> file format off hand), you could send us the actual data so we can try to 
> read it in, but at the least str() will let us see how R is storing your data 
> and give you some explanation.
>
> Side note, as data() is a function, it might be worthwhile to call your 
> actual data something else (say, mydata, dat, etc.).  For anyone else 
> interested, readMat() is in package "R.matlab".
>
> Cheers,
>
> Josh
>
> On Sun, Mar 13, 2011 at 2:07 PM, Eduardo M. A. M.Mendes 
> <emammen...@gmail.com> wrote:
>> Hello
>>
>> I have a matlab MAT file that contains one single variable: a.  The 
>> structure of a is as follows:
>>
>> a.river1.flow (flow values)
>> a.river1.date_flow (date)
>> a.river1.precip (precipitation values) a.river1.date_precip 
>> a.river2.flow a.river2.date_flow a.river2.precip a.river2.date_precip
>>
>> I have used readMat to load the variable a in R, however I have no 
>> idea how readMat translates a.  I managed to get some values out of
>> data=readMat("matfile.mat")
>>
>> data$a[,,1]$river1[,,1]$flow  -> Why do I need [,,1]?  Why not 
>> data$a$river1$flow?
>>
>> Many thanks
>>
>> Ed
>>
>> ______________________________________________
>> R-help@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.

--
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/

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