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

[Moshe Olshansky]

Assuming that your data is in a data.frame d, you could do the following:

for (i in 1:999)
{
df <- d[564*(i-1)+(1:564),]
g <- paste("group",i,sep="")
group <- rep(g,564)
newdf <- data.frame(group,df)
filename <- paste("file",i,".csv",sep="")
write.csv(newdf,filename)
}


--- On Tue, 3/6/08, joshgage <joshgage at gmail.com> wrote:

> From: joshgage <joshgage at gmail.com>
> Subject: [R]  Partitioning a large data frame and writing output CSVs
> To: r-help at r-project.org
> Received: Tuesday, 3 June, 2008, 10:58 AM
> 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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