The error message says there is no method for
converting from 'character' to 'raw'.
Apparently, R is seeing character data in the
file, and is trying to convert it to raw, since
you specified raw, and it can't.
See, for example,
as('aa','raw')
Error in as("aa", "raw") :
no method or default for coercing "character" to "raw"
(same error message)
So I would ask, what are your data, really? Why
are you asking for raw? Have you checked the help
page for raw to make sure it's what you want?
-Don
At 5:23 PM +0100 2/11/10, Ivan Calandra wrote:
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Well, it's too complicated for me! Here are what I would do (limited
since I'm still a newbie)
1) the syntax seems correct, it should work. The problem is somewhere
else, coming from your own file. Did you try skipping the colClasses
argument? To see how it looks like... If you can import it that way, try
str(x) to see what you have. It might help you.
2) I've never had that much data to import, and for me read.table works
well.
You might want to wait for the experts!
Ivan
Le 2/11/2010 17:14, Johan Jackson a écrit :
Hi Ivan,
Thanks for the reply. Damn IT! My original post was screwed up. HERE
is what I did:
x <- read.table("data",header=TRUE,colClasses=rep('raw',600000))
#returns error: no method or default for coercing "character" to "raw"
I've read the ?read.table and the colClasses argument. I'm still unclear:
1) colClasses is a character vector, is that right? That seems to be
what the help says, but I get an error when I do the above.
2) what is the most efficient way to read in huge amounts of data? In
the past I found that scan() and readLines() were slower than read.table.
Thanks,
JJ
On Thu, Feb 11, 2010 at 8:53 AM, Ivan Calandra
<ivan.calan...@uni-hamburg.de <mailto:ivan.calan...@uni-hamburg.de>>
wrote:
Hi!
|"colClasses| character. A vector of classes to be assumed
for the
columns."
I'm not an R expert and I don't know what your "flat file raw" is, but
the colClasses argument is to define whether the column will be
treated
as containing "factors", "logical", "integer" etc...
For more on read.table, read the manual "R Data Import/Export"
available
on the R-project website.
I don't know if it helps, but I hope it does!
>
> Ivan
>
> Le 2/11/2010 16:36, Johan Jackson a écrit :
> > Hi all,
> >
> > First off, it is surprising that there are no examples of how to use
> > read.table() under ?read.table !
>
> I am trying to read in a flat file of type 'raw'. It has 1000
rows and 600K
> columns. I have the RAM to accomplish this, but can't get the
data into R
> using read.table:
>
> x<- read.table("data",header=TRUE,colClasses=rep(,600000))
> #returns error: no method or default for coercing "character"
to "raw"
>
> Then I thought that maybe the colClasses vector needed to
actually *be* the
> mode needed (here's where an example under ?read.table would help):
>
> x<- read.table("data",header=TRUE,colClasses=rep(as.raw(1),600000))
>
> I waited on the latter command for a couple of hours before
killing the
> process. What should the colClasses argument be?
>
> Should I be using another method to read the data into R? Previous
> experience using scan() and readLines() showed that read.table()
was faster,
> at least for those examples, so I've stopped trying to use those
other
> functions.
>
> Thank you,
>
> JJ
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org <mailto: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.
>
>
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______________________________________________
R-help@r-project.org <mailto:R-help@r-project.org> mailing list
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PLEASE do read the posting guide
http://*www.*R-project.org/posting-guide.html
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______________________________________________
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PLEASE do read the posting guide http://*www.*R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062
______________________________________________
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