Re: [R] Partitioning a large data frame and writing output CSVs

From: jim holtman <jholtman_at_gmail.com>
Date: Mon, 02 Jun 2008 21:50:57 -0400

This might give you a hint of how to do it. BTW, were the dimensions 563436x4?

test <- matrix(runif(100*4),ncol=4)
# create groups of 10 rows
group <- rep(1:10, each=10)
new.test <- cbind(test, group=group)
# now get indices to write out
indices <- split(seq(nrow(test)), new.test[, 'group']) # now write out the files
for (i in names(indices)){

    write.csv(new.test[indices[[i]],], file=paste("data.", i, ".csv", sep=""),

        row.names=FALSE)
}

On Mon, Jun 2, 2008 at 8:58 PM, joshgage <joshgage_at_gmail.com> wrote:

>
> Hello,
>
> I have a large dataset [536436,4]
>
> I'd like to partition the dataset into 999 groups of 564 rows and output
> each group as a CSV files... Obviously I could do this longhand but I know
> it is somehow possible to write a loop to do the same thing...
>
> I'd like to group such that the first group is the first 564 rows, the
> second group is the second 564 rows ..... the 999th group is the 999th 564
> rows...
>
> In each newly created group, I'd like there to be a new column that
> identifies the group... i.e. the first group would have a new column in
> which all 564 observations have a character value of "group1"
>
> Finally I'd also like to output each one of these groups as a CSV file with
> a unique name....
>
> Any help with this is very greatly appreciated....
>
> thanks in advance,
>
> Josh
> --
> View this message in context:
> http://www.nabble.com/Partitioning-a-large-data-frame-and-writing-output-CSVs-tp17614022p17614022.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
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>

-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

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Received on Tue 03 Jun 2008 - 02:25:19 GMT

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