[R] how to "singlify" entries

[Petr Pikal]

On 30 May 2005 at 21:56, Charles Plessy wrote:

> On Mon, May 30, 2005 at 09:15:32AM +0000, zhihua li wrote :
> > hi netters
> > 
> > I have a rather simple question.  I have a data frame with two
> > variables X and Y, both of which are factors. X has 100 levels while
> > Y has 10 levels only. The data frame has 100 rows in all, so for X
> > the values are unique, and Y has many replicate values.  Now I wanna
> > reduce the data frame into 10 rows only, according to the 10 levels
> > of Y.  I don't care which value of X is in the same row with Y in
> > the final data frame, as long as it is in agreement with the
> > original data frame.
> 
> Dear list,
> 
> I am a new subscriber, using R to analyse genomics data. I have a
> similar question, maybe even identical, but I am not sure...

Hallo

Me neither.

?reshape

> dat<-read.table("clipboard", header=T)
> dat
  F1 F2 V
1  A  X 3
2  A  Y 6
3  B  X 5
4  C  X 9
5  C  Y 3
> reshape(dat, idvar="F1", timevar="F2",direction="wide")
  F1 V.X V.Y
1  A   3   6
3  B   5  NA
4  C   9   3


Homework: change NA to zero.

HTH
Petr

> 
> >From a data frame with two factors and one value, I would like to
> >obtain a data
> frame with one factor and one value per level in the removed factor.
> 
> For instance:
> 
> F1      F2      V
> -----------------
> A       X       3
> A       Y       6
> B       X       5
> C       X       9
> C       Y       3
> 
> Would become:
> 
> F1      VX      VY
> ------------------
> A       3       6
> B       5       0
> C       9       3
> 
> I am sure I have seen a tool to do this some time ago, but I do not
> remember its name.
> 
> Can somebody help me ?
> 
> Best regards,
> 
> -- 
> Charles Plessy, Ph.D. - Genome Science Laboratory
> The Institute for Physical and Chemical Research (RIKEN)
> 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
> plessy at riken.jp --  Fax: 048-462-4686  --  Tel: 048-467-9515
> 
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Petr Pikal
petr.pikal at precheza.cz