Data manipulation in a data.frame

This is easy to do in the approach I showed.

Instead of:
names(A)[-1][as.matrix(A[,-1])%*%(seq_len(ncol(A)-1))]
modify it to:
c("none",names(A)[-1])[as.matrix(A[,-1])%*%seq_len(ncol(A)-1)+1]
[1] "D"    "B"    "B"    "B"    "C"    "C"    "D"    "none"

Cheers,
Bert

Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
H. Gilbert Welch
Thank you very much. One further question.

Assuming that for some points there is no classification for example:

A<-data.frame(A=c(10,100,1000,30,50,60,300,3),

              B=c(0,1,1,1,0,0,0,0),

              C=c(0,0,0,0,1,1,0,0),

              D=c(1,0,0,0,0,0,1,0))

Is there an easy way to introduce an extra none option in the variable?

A<-data.frame(A=c(10,100,1000,30,50,60,300,3),

              B=c(0,1,1,1,0,0,0,0),

              C=c(0,0,0,0,1,1,0,0),

              D=c(1,0,0,0,0,0,1,0),

       Variable=c(D,B,B,B,C,C,D,none))

Thanks in advance,
IOanna

-----Original Message-----
From: arun [mailto:smartpink111 at yahoo.com]
Sent: 21 February 2014 00:19
To: r-help at r-project.org
Cc: ioanna ioannou
Subject: Re: [R] Data manipulation in a data.frame

Also,
rownames(which(t(!!A[,-1]),arr.ind=TRUE))
A.K.

On Thursday, February 20, 2014 6:48 PM, arun <smartpink111 at yahoo.com> wrote:
Hi,
May be this helps:

A$Variable <- rep(colnames(A[,-1]),nrow(A))[t(!!A[,-1])]
A.K.

On Thursday, February 20, 2014 5:55 PM, ioanna ioannou <ii54250 at msn.com>
wrote:
Hello,

Assuming that I have a data frame

A<-data.frame(A=c(10,100,1000,30,50,60,300),

              B=c(0,1,1,1,0,0,0),

              C=c(0,0,0,0,1,1,0),

              D=c(1,0,0,0,0,0,1))

What I would like is to introduce a new column Variable such that:

A<-data.frame(A=c(10,100,1000,30,50,60,300),

              B=c(0,1,1,1,0,0,0),

              C=c(0,0,0,0,1,1,0),

              D=c(1,0,0,0,0,0,1),

       Variable=c(D,B,B,B,C,C,D))

How can I do it?

Best

IOanna

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Data manipulation in a data.frame

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