[R] Matrices with a single column

[Huntsinger, Reid]

There's an optional "drop" argument to the indexing operations, which is by
default TRUE. You just want 

> x[4:6,,drop=FALSE]
     [,1]
[1,]    4
[2,]    5
[3,]    6

Reid Huntsinger

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Crispin Miller
Sent: Thursday, September 01, 2005 10:54 AM
To: R-help at stat.math.ethz.ch
Subject: [R] Matrices with a single column


Hi,
I've got a quick question about what happens when indexing into matrices
with a single column. I was wondering if anyone can help ...
 
For example:
> x <- matrix(1:10)

> y <- cbind(x,x)

> x[4:6,]

[1] 4 5 6

> y[4:6,]

   [,1] [,2]

[1,] 4 4

[2,] 5 5

[3,] 6 6

> class(x[4:6,])

[1] "integer"

> class(y[4:6,])

[1] "matrix"

It seems that R is returning the results of indexing into a matrix with
one column as a vector rather than a matrix?

Does anyone have a good way of preventing this from happening?

cheers,

crispin
 
--------------------------------------------------------

 
This email is confidential and intended solely for the use o...{{dropped}}

______________________________________________
R-help at stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html