[R] combine two columns

[Petr Pikal]

Hallo

On 28 Nov 2005 at 18:47, Georg Otto wrote:

To:             	r-help at stat.math.ethz.ch
From:           	Georg Otto <georg.otto at tuebingen.mpg.de>
Date sent:      	Mon, 28 Nov 2005 18:47:38 +0100
Subject:        	[R] combine two columns

> Hi,
> 
> I have an R programming problem and I havent found anything in the
> documentation yet:
> 
> I have a data matrix, in which two neighbouring columns represent
> replicates of the same experiment, e.g. something like this:
> 
>        A A B B C C
> row1   1 1 1 2 2 2
> row2   1 1 1 1 1 2

Not very neat but

> tabul
      A A.1 B B.1 C C.1 
 row1 1   1 1   2 2   2
 row2 1   1 1   1 1   2

 > logmat<-as.logical(apply(tabul,1,diff))
 > dim(logmat)<-c(2,5)
 > logmat
       [,1]  [,2]  [,3]  [,4]  [,5]
 [1,] FALSE  TRUE FALSE FALSE FALSE
 [2,] FALSE FALSE FALSE FALSE  TRUE


 > liche
 function (x) 
 {
     indices <- seq(along = x)
     x[indices%%2 == 1]
 }

 > !logmat[,liche(1:5)]
     [,1] [,2]  [,3]
[1,] TRUE TRUE  TRUE
[2,] TRUE TRUE FALSE
>

Finally gives the result you want.

HTH
Petr

> 
> I would like to test, if the values for the two replicates in a row
> are the same or if they differ and generate a new matrix with the
> results of the tests, something like this:
> 
>         A B C
> row1    T F T
> row2    T T F
> 
> Any hint will be appreciated!
> 
> Georg
> 
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Petr Pikal
petr.pikal at precheza.cz