Re: [R] Converting a data frame with values into a matrix/

From: Henrique Dallazuanna <wwwhsd_at_gmail.com>
Date: Wed, 12 Mar 2008 14:32:16 -0300

Perhaps in this case:

noquote(with(xx, tapply(NES, list(Class, Name), paste)))

On 12/03/2008, Srinivas Iyyer <srini_iyyer_bio_at_yahoo.com> wrote:
> Dear Group,
> I have a data frame like the following:
>
>
> x <- c("Mike","A",0.01)
> x1 <- c("Carl","A",0.2)
> x2 <- c("Gene","C",0.3)
> x3 <- c("James","A",-0.3)
> x4 <- c("Dough","B",0)
> xx <- rbind(x,x1,x2,x3,x4)
> colnames(xx)<-c("Name","Class","NES")
> xx <-as.data.frame(xx)
>
> > xx
> Name Class NES
> x Mike A 0.01
> x1 Carl A 0.2
> x2 Gene C 0.3
> x3 James A -0.3
> x4 Dough B 0
>
>
> Now I want to create a matrix with unique xx$Name on
> columns and unique xx$Class as rows. I want to fill
> my choice of values (in this case 1) if data point not
> available.
>
>
> xy <-
> matrix(1,length(unique(xx$Class)),length(unique(xx[,1])))
> colnames(xy)<-unique(xx[,1])
> rownames(xy)<-unique(xx$Class)
>

> > xy
> Mike Carl Gene James Dough
> A 1 1 1 1 1
> C 1 1 1 1 1
> B 1 1 1 1 1
>
>
>
>
>
> I would love to have :
>
> Mike Carl Gene James Dough
> A 0.01 0.2 1 -0.3 1
> C 1 1 1 0.3 1
> B 1 1 1 1 0
>
>
>
>
> If I am not wrong this is called contigency or
> frequeny table.
>
> I tried xtabs on this.
>
> > z <- xtabs(NES ~ Name+Class,data=xx)
> Error in Summary.factor(4L, na.rm = FALSE) :
> sum not meaningful for factors
>
>
> I tried on other data frames, it worked. BUT the
> problem is it gives me 0.0000 even a value is not
> available for that row and column. So if I have data
> -0.00 it is considered 0.
>
> I tried. drop.unused.levels = T, I did not get what I
> want. I want all row.col values not available to be 1.
>
>
> Is there any other trick where I map by row and column
> names instead of using advanced xtabs.
>
> thanks
> Srini
>
> ______________________________________________
> 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-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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Received on Wed 12 Mar 2008 - 17:55:12 GMT

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