R help - Sep 2011 - problems to report indexes when I have two min value

Hi,

I need to repor the index of a min value of each row in a matrix, but I
don't know how to do that when I have more than one min value.

Here is my example
> dat <-
matrix(c(5.4,4.8,5.6,4.8,NA,4.4,4.6,3.4,NA,NA,4,2.4,NA,NA,NA,2),byrow=TRUE,ncol=4)
> dat
     [,1] [,2] [,3] [,4]
[1,]  5.4  4.8  5.6  4.8
[2,]   NA  4.4  4.6  3.4
[3,]   NA   NA  4.0  2.4
[4,]   NA   NA   NA  2.0
> k <- apply(dat, 1, function(x) which(x == min(x, na.rm = TRUE)))
>    k
[[1]]
[1] 2 4

[[2]]
[1] 4

[[3]]
[1] 4

[[4]]
[1] 4

But I need an output like this

k<- 2 or 4, 4, 4, 4

Someone could help me with this issue.

Thanks in advance,

Marlene.

	[[alternative HTML version deleted]]

Your coded answer looks right, and is represented in a syntactically correct
manner. Your "desired" answer looks ambiguous, and is certainly not
syntactically correct R. If you want ambiguous and vague answers, perhaps you
need to keep a human in the loop.
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Sent from my phone. Please excuse my brevity.

marlene marchena <marchenamarlene@gmail.com> wrote:

Hi,

I need to repor the index of a min value of each row in a matrix, but I
don't know how to do that when I have more than one min value.

Here is my example
> dat <-
matrix(c(5.4,4.8,5.6,4.8,NA,4.4,4.6,3.4,NA,NA,4,2.4,NA,NA,NA,2),byrow=TRUE,ncol=4)
> dat
[,1] [,2] [,3] [,4]
[1,] 5.4 4.8 5.6 4.8
[2,] NA 4.4 4.6 3.4
[3,] NA NA 4.0 2.4
[4,] NA NA NA 2.0
> k <- apply(dat, 1, function(x) which(x == min(x, na.rm = TRUE)))
> k
[[1]]
[1] 2 4

[[2]]
[1] 4

[[3]]
[1] 4

[[4]]
[1] 4

But I need an output like this

k<- 2 or 4, 4, 4, 4

Someone could help me with this issue.

Thanks in advance,

Marlene.

	[[alternative HTML version deleted]]

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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


	[[alternative HTML version deleted]]

Hi there,
Assuming you would prefer to have only one min per row:

apply(dat,1,which.min)

there is a link to this function in the help page for ?min.
JC

2011/9/16 marlene marchena <marchenamarlene at
gmail.com>:
> Hi,
>
> I need to repor the index of a min value of each row in a matrix, but I
> don't know how to do that when I have more than one min value.
>
> Here is my example
>
>> dat <-
>
matrix(c(5.4,4.8,5.6,4.8,NA,4.4,4.6,3.4,NA,NA,4,2.4,NA,NA,NA,2),byrow=TRUE,ncol=4)
>
>> dat
> ? ? [,1] [,2] [,3] [,4]
> [1,] ?5.4 ?4.8 ?5.6 ?4.8
> [2,] ? NA ?4.4 ?4.6 ?3.4
> [3,] ? NA ? NA ?4.0 ?2.4
> [4,] ? NA ? NA ? NA ?2.0
>> k <- apply(dat, 1, function(x) which(x == min(x, na.rm = TRUE)))
>> ? ?k
> [[1]]
> [1] 2 4
>
> [[2]]
> [1] 4
>
> [[3]]
> [1] 4
>
> [[4]]
> [1] 4
>
> But I need an output like this
>
> k<- 2 or 4, 4, 4, 4
>
> Someone could help me with this issue.
>
> Thanks in advance,
>
> Marlene.
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>