[R] Filling data frame data into a matrix - please help

[Henrique Dallazuanna]

Try this:

d1 <- data.frame(d1)
d1$V3 <- as.numeric(as.character(d1$V3))
xtabs(V3 ~ r1+c1, data=d1)

You can substitute 0 with NA:

d1.tb <- xtabs(V3 ~ r1+c1, data=d1)
d1.tb[d1.tb==0] <- NA


On 24/01/2008, Srinivas Iyyer <srini_iyyer_bio at yahoo.com> wrote:
> Dear group,
> I have a data.frame (d1) with various elements and a
> matrix (m1) created with NA (or 1s). I want to read
> each row,column in d1 and fill its numeric value in
> m1.
>
> Could some one help me because I have 130K rows and
> 500 column data.frame object and I was told that a for
> loop will take a long time.
>
> Thank you.
>
> > r1 <- c("A","A","B","B")
> > c1 <- c("Apple","Andy","Boy","Ball")
> > v1 <- as.numeric(c(0.001,0.02,0.3,NA))
> > d1 <- cbind(r1,c1,as.numeric(v1))
> > d1 <- data.frame(d1)
> > d1
>   r1    c1    V3
> 1  A Apple 0.001
> 2  A  Andy  0.02
> 3  B   Boy   0.3
> 4  B  Ball  <NA>
>
>
> > m1 <- matrix(NA,2,4)
> > rownames(m1)<- unique(r1)
> > colnames(m1)<-unique(c1)
> > m1
>   Apple Andy Boy Ball
> A    NA   NA  NA   NA
> B    NA   NA  NA   NA
>
>
> I want to have:
>
> result:
>
>
>   Apple   Andy  Boy  Ball
> A 0.001   0.02  NA    NA
> B  NA     NA    0.3   NA
>
>
> thanks
> Srini
>
>
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-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O