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jjap

2011-Mar-29 18:15 UTC

[R] Simple but elusive - expand back from counts

Dear R-users,

This should be simple but still eludes me:

Given the following
tmp<-as.data.frame(matrix(c(44, 10, "abc", 1, 44, 10,
"def", 1, 44, 12,
"abc", 2), 3, 4, byrow=T))

I want to  expand the data to the following form:

  V1 V2  V3 V4
1 44 10 abc  1
2 44 10 def  1
3 44 12 abc  1
4 44 12 abc  1

The last row of the original df was duplicated the row by the number in the
4th column (which could be expendable being all ones)
I clumsily tried a few variants of a loop but I am not making any progress.
Any hints would be greatly appreciated.
for (i in 1:3){
  rbind(rep(tmp[i,], temp[i,4])
  }

--
View this message in context:
http://r.789695.n4.nabble.com/Simple-but-elusive-expand-back-from-counts-tp3415727p3415727.html
Sent from the R help mailing list archive at Nabble.com.

Joshua Wiley

2011-Mar-29 19:16 UTC

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[R] Simple but elusive - expand back from counts

Hi,

You can use rep() to repeat the appropriate rows as in V4.  For example:

tmp[rep(rownames(tmp), tmp$V4), ]

    V1 V2  V3 V4
1   44 10 abc  1
2   44 10 def  1
3   44 12 abc  2
3.1 44 12 abc  2

if you wanted, you could then reset the row names to NULL to get 1, 2,
3, 4 rather than 3, 3.1

rownames(tmp) <- NULL ## AFTER saving the expanded form.

Cheers,

Josh

On Tue, Mar 29, 2011 at 11:15 AM, jjap <sabjap at gmail.com>
wrote:> Dear R-users,
>
> This should be simple but still eludes me:
>
> Given the following
> tmp<-as.data.frame(matrix(c(44, 10, "abc", 1, 44, 10,
"def", 1, 44, 12,
> "abc", 2), 3, 4, byrow=T))
>
> I want to ?expand the data to the following form:
>
> ?V1 V2 ?V3 V4
> 1 44 10 abc ?1
> 2 44 10 def ?1
> 3 44 12 abc ?1
> 4 44 12 abc ?1
>
> The last row of the original df was duplicated the row by the number in the
> 4th column (which could be expendable being all ones)
> I clumsily tried a few variants of a loop but I am not making any progress.
> Any hints would be greatly appreciated.
> for (i in 1:3){
> ?rbind(rep(tmp[i,], temp[i,4])
> ?}
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Simple-but-elusive-expand-back-from-counts-tp3415727p3415727.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at 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/

Peter Alspach

2011-Mar-29 19:17 UTC

head link

[R] Simple but elusive - expand back from counts

Tena koe

Try something like:

tmp[rep(1:nrow(tmp), each=tmp[,4]),] # untested

HTH ...

Peter Alspach
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of jjap
> Sent: Wednesday, 30 March 2011 7:16 a.m.
> To: r-help at r-project.org
> Subject: [R] Simple but elusive - expand back from counts
> 
> Dear R-users,
> 
> This should be simple but still eludes me:
> 
> Given the following
> tmp<-as.data.frame(matrix(c(44, 10, "abc", 1, 44, 10,
"def", 1, 44, 12,
> "abc", 2), 3, 4, byrow=T))
> 
> I want to  expand the data to the following form:
> 
>   V1 V2  V3 V4
> 1 44 10 abc  1
> 2 44 10 def  1
> 3 44 12 abc  1
> 4 44 12 abc  1
> 
> The last row of the original df was duplicated the row by the number in
> the
> 4th column (which could be expendable being all ones)
> I clumsily tried a few variants of a loop but I am not making any
> progress.
> Any hints would be greatly appreciated.
> for (i in 1:3){
>   rbind(rep(tmp[i,], temp[i,4])
>   }
> 
> --
> View this message in context: http://r.789695.n4.nabble.com/Simple-but-
> elusive-expand-back-from-counts-tp3415727p3415727.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at 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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Petr Savicky

2011-Mar-29 19:18 UTC

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[R] Simple but elusive - expand back from counts

On Tue, Mar 29, 2011 at 11:15:33AM -0700, jjap wrote:> Dear R-users,
> 
> This should be simple but still eludes me:
> 
> Given the following
> tmp<-as.data.frame(matrix(c(44, 10, "abc", 1, 44, 10,
"def", 1, 44, 12,
> "abc", 2), 3, 4, byrow=T))
> 
> I want to  expand the data to the following form:
> 
>   V1 V2  V3 V4
> 1 44 10 abc  1
> 2 44 10 def  1
> 3 44 12 abc  1
> 4 44 12 abc  1
> 
> The last row of the original df was duplicated the row by the number in the
> 4th column (which could be expendable being all ones)
Hi.

Try the following.

  tmp1 <- tmp[rep(1:nrow(tmp), times=tmp$V4), ]
  tmp1$V4 <- 1
  row.names(tmp1) <- NULL
  tmp1

    V1 V2  V3 V4
  1 44 10 abc  1
  2 44 10 def  1
  3 44 12 abc  1
  4 44 12 abc  1

Hope this helps.

Petr Savicky.

Henrique Dallazuanna

2011-Mar-29 19:19 UTC

head link

[R] Simple but elusive - expand back from counts

Try this:

transform(tmp[rep(seq(nrow(tmp)), as.numeric(tmp$V4)),], V4 = 1)

On Tue, Mar 29, 2011 at 3:15 PM, jjap <sabjap at gmail.com>
wrote:> Dear R-users,
>
> This should be simple but still eludes me:
>
> Given the following
> tmp<-as.data.frame(matrix(c(44, 10, "abc", 1, 44, 10,
"def", 1, 44, 12,
> "abc", 2), 3, 4, byrow=T))
>
> I want to ?expand the data to the following form:
>
> ?V1 V2 ?V3 V4
> 1 44 10 abc ?1
> 2 44 10 def ?1
> 3 44 12 abc ?1
> 4 44 12 abc ?1
>
> The last row of the original df was duplicated the row by the number in the
> 4th column (which could be expendable being all ones)
> I clumsily tried a few variants of a loop but I am not making any progress.
> Any hints would be greatly appreciated.
> for (i in 1:3){
> ?rbind(rep(tmp[i,], temp[i,4])
> ?}
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Simple-but-elusive-expand-back-from-counts-tp3415727p3415727.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at 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.
>


-- 
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O

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