Re: [R] naming rows/columns in 'array of matrices'
> > I'd also be interested in why the 'direct, brute force' approach
> > (above) doesn't work,
Your example was a 3-dimensional array, so
> rownames(P) <- colnames(P) <- c(live', 'dead')
would have worked; rownames() and colnames() work on dimnames[1] and
dimnames[2].
But
rownames(P[,,1])
could not have worked, because you were not assigning to the names of P; you
were assigning to something (P[,,1]) extracted from P. In effect, you were
doing the equivalent of
{P1 <- P[,,1]
rownames(P1) <- c('live', 'dead')
rm(P1)}
> > ... since I might need to manipulate
> > row/col names for individual matrices in the array (if, say,
> > dimensions of the matrices were not the same over the array).
If the dimension are different you will not have an array; you'd have to have a
list of matrices.
You could then use lapply for the one constant dimension size; for example,
lp <- list(P22 = matrix(ncol=2, nrow=2), P32= matrix(ncol=2, nrow=3))
lapply(lp, function(x, cn=c('live', 'dead')) {colnames(x)<-cn; x})
Other than that, you'd either have to do some careful conditional coding or
apply names manually.
S
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Re: [R] naming rows/columns in 'array of matrices'
In your example, P is a three dimensional array. You can assign names to
the three dimensions using the dimnames() function. For example, this
command assigns names to the first two dimensions, but leaves the third
dimension without names.
dimnames(P) <- list(c("live", "dead"), c("live", "dead"), NULL)
Jean
On Fri, Jan 30, 2015 at 1:07 PM, Evan Cooch wrote:
> Suppose I have the following situation:
>
> I have an array of 2 matrices, where each matrix is (2x2):
>
> P <- array(0, c(2,2,2))
>
> P[,,1] <- matrix(c(1,2,3,4),2,2,byrow=T);
> P[,,2] <- matrix(c(5,6,7,8),2,2,byrow=T);
>
> I want to label rows and columns of each matrix in the array, such that P
> would look like
>
>
> live dead
> live 12
> dead 34
>
> , , 2
>
> live dead
> live 56
> dead 78
>
> I've tried 'direct, brute force" approaches like
>
> rownames(P[,,1]) <- c("live","dead")
> colnames(P[,,1]) <- c("live","dead")
>
> (repeated for the second matrix), but this doesn't work.
>
> Since all of the matrices are of the same dimension(s), and since I want
> the same rownames and colnames for each matrix, I'm hoping there is some
> simply magical permutation of lapply (I'm guessing) which will do the trick.
>
> I'd also be interested in why the 'direct, brute force' approach (above)
> doesn't work, and what does, since I might need to manipulate row/col names
> for individual matrices in the array (if, say, dimensions of the matrices
> were not the same over the array).
>
> Thanks in advance!
>
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>
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Re: [R] naming rows/columns in 'array of matrices' | solved
You can also add names to the dimensions:
> dimnames(P)[[1]] <- c("live","dead")
> dimnames(P)[[2]] <- c("old","young")
> names(dimnames(P)) <- c("status", "age", NULL)
> P
, , 1
age
status old young
live 1 2
dead 3 4
, , 2
age
status old young
live 5 6
dead 7 8
David L. Carlson
Department of Anthropology
Texas A&M University
-Original Message-
From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of peter dalgaard
Sent: Saturday, January 31, 2015 2:19 AM
To: Evan Cooch
Cc: r-help@r-project.org
Subject: Re: [R] naming rows/columns in 'array of matrices' | solved
> On 30 Jan 2015, at 20:34 , Evan Cooch wrote:
>
> The (obvious, after the fact) solution at the bottom. D'oh...
>
[snip]
> Forgot I was dealing with a multi-dimensional array, not a list. So,
> following works fine. I'm sure there are better approaches (where 'better' is
> either 'cooler', or 'more flexible'), but for the moment...)
>
> P <- array(0, c(2,2,2),dimnames=list(c("live","dead"),c("old","young"),NULL))
>
> P[,,1] <- matrix(c(1,2,3,4),2,2,byrow=T);
> P[,,2] <- matrix(c(5,6,7,8),2,2,byrow=T);
>
> print(P);
>
Just for completeness, this also works:
> P <- array(0, c(2,2,2))
> P[,,1] <- matrix(c(1,2,3,4),2,2,byrow=T);
> P[,,2] <- matrix(c(5,6,7,8),2,2,byrow=T);
> dimnames(P)[[1]] <- c("live","dead")
> dimnames(P)[[2]] <- c("live","dead")
--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd@cbs.dk Priv: pda...@gmail.com
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Re: [R] naming rows/columns in 'array of matrices' | solved
> On 30 Jan 2015, at 20:34 , Evan Cooch wrote:
>
> The (obvious, after the fact) solution at the bottom. D'oh...
>
[snip]
> Forgot I was dealing with a multi-dimensional array, not a list. So,
> following works fine. I'm sure there are better approaches (where 'better' is
> either 'cooler', or 'more flexible'), but for the moment...)
>
> P <- array(0, c(2,2,2),dimnames=list(c("live","dead"),c("old","young"),NULL))
>
> P[,,1] <- matrix(c(1,2,3,4),2,2,byrow=T);
> P[,,2] <- matrix(c(5,6,7,8),2,2,byrow=T);
>
> print(P);
>
Just for completeness, this also works:
> P <- array(0, c(2,2,2))
> P[,,1] <- matrix(c(1,2,3,4),2,2,byrow=T);
> P[,,2] <- matrix(c(5,6,7,8),2,2,byrow=T);
> dimnames(P)[[1]] <- c("live","dead")
> dimnames(P)[[2]] <- c("live","dead")
--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd@cbs.dk Priv: pda...@gmail.com
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Re: [R] naming rows/columns in 'array of matrices' | solved
The (obvious, after the fact) solution at the bottom. D'oh...
On 1/30/2015 2:07 PM, Evan Cooch wrote:
Suppose I have the following situation:
I have an array of 2 matrices, where each matrix is (2x2):
P <- array(0, c(2,2,2))
P[,,1] <- matrix(c(1,2,3,4),2,2,byrow=T);
P[,,2] <- matrix(c(5,6,7,8),2,2,byrow=T);
I want to label rows and columns of each matrix in the array, such
that P would look like
live dead
live 12
dead 34
, , 2
live dead
live 56
dead 78
I've tried 'direct, brute force" approaches like
rownames(P[,,1]) <- c("live","dead")
colnames(P[,,1]) <- c("live","dead")
(repeated for the second matrix), but this doesn't work.
Since all of the matrices are of the same dimension(s), and since I
want the same rownames and colnames for each matrix, I'm hoping there
is some simply magical permutation of lapply (I'm guessing) which will
do the trick.
Forgot I was dealing with a multi-dimensional array, not a list. So,
following works fine. I'm sure there are better approaches (where
'better' is either 'cooler', or 'more flexible'), but for the moment...)
P <- array(0,
c(2,2,2),dimnames=list(c("live","dead"),c("old","young"),NULL))
P[,,1] <- matrix(c(1,2,3,4),2,2,byrow=T);
P[,,2] <- matrix(c(5,6,7,8),2,2,byrow=T);
print(P);
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