[R] two questions
Christoph Lange
clange at epost.de
Mon Apr 15 18:42:47 CEST 2002
(Reply to Ambrosini Alessandro)
> The first: if I have a vector as (1,1,3,2,1,1), which is the command that
> gives all the positions of the min value? From the vector of the example a
> would like to obtain a new vector as (1,2,5,6) that give me all the
> positions of the minimum value 1.
> x <- c(1,1,3,2,1,1)
> x[x==min(x)]
[1] 1 1 1 1
> which(x==min(x))
[1] 1 2 5 6
>
> The second: if I have a matrix "A" and I want to obtain a new matrix
> deleting a column or a row of A, what have I to do?
> A
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
> A[,-2]
[,1] [,2]
[1,] 1 7
[2,] 2 8
[3,] 3 9
> A[-2,]
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 3 6 9
>
That's the solutions.
Christoph.
--
Christoph Lange clange at epost.de
Verhaltensbiologie, FU Berlin 838-55068
Haderslebener Str. 9, 12163 Berlin
http://www.verhaltensbiologie.fu-berlin.de/
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