[R] conditional output of string to file n times...

[Eric Berger]

Hi Evan,
I assume you know how to get the data into a data frame (e.g. via read.csv).
Here I will create the example data explicitly, creating a data frame x.

x <- data.frame( label=c("ABC","DDG","ABB"), count=c(3,5,2) )

Then create a character vector with the data as you want it.

y <- unlist(sapply( 1:nrow(x), function(i) rep( x$label[i], x$count[i] ) ))

Finally print it to a file, say 'myfile' (to get one element per line I did
a bit of a trick).

write.table(x=t(t(y)),file="myfile",row.names=FALSE,col.names=FALSE,quote=FALSE)

HTH,
Eric




On Wed, Jul 7, 2021 at 10:15 AM Evan Cooch <evan.cooch using gmail.com> wrote:

> Suppose I have a file with the the following structure - call the two
> space-separated fields 'label' and 'count':
>
> ABC 3
> DDG 5
> ABB 2
>
>
> What I need to do is parse each line of the file, and then depending on
> the value of count, write out the value of 'label' to a new file, but
> 'count' times. In other words, take the preceding, and output
>
> ABC
> ABC
> ABC
> DDG
> DDG
> DDG
> DDG
> DDG
> ABB
> ABB
>
> I was wondering if there was an elegant/simple way to do this? I can do
> this relatively easily in perl, or awk, but am stumped by getting a bit
> of R code to accomplish the same thing.
>
> Many thanks in advance...
>
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