[R] Re : Problem with a Matrix

[Pascal Oettli]

Hi Hamada,

Could the following be helpful?

"dtf" is your data.frame 


nr <- nrow(dtf)
new.dtf <- data.frame(Site.No=seq(1,nr/2))
new.dtf$XXX <- dtf[seq(1,nr,2),3]
new.dtf$YYY <- dtf[seq(2,nr,2),3]

or

new.mat <- numeric()
new.mat <- cbind(new.mat,dtf[seq(1,nr,2),3])
new.mat <- cbind(new.mat,dtf[seq(2,nr,2),3])


Regards,
Pascal



----- Mail original -----
De : Hamada Elsayed Ali <medo_botany at hotmail.com>
À : r-help at r-project.org
Cc : 
Envoyé le : Jeudi 8 mars 2012 18h20
Objet : [R] Problem with a Matrix

Dear All,

I have a problem in making a matrix from a data. I did a summary data from a
big data frame using (ddply), the resulting table is like that:

Site.No    Plant.Name    Cover.Percentage
1                XXX                15
1                YYY                 20
2                XXX                18
2                YYY                 21
3                XXX                14
3                YYY                 26

I need to convert it to the following:

        XXX      YYY
1      15        20
2      18        21
3      14        26

I tried for the whole day yesterday but I can't solve it. Could you please
help me.

Thanks in advance for all of you,
Hamada

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