From: Robin Hankin <r.hankin_at_noc.soton.ac.uk>

Date: Tue 16 Jan 2007 - 10:10:42 GMT

[1,] 1

Date: Tue 16 Jan 2007 - 10:10:42 GMT

The following gotcha caught me off-guard just now.

a <- matrix(1,3,3)

b <- matrix(1,1,1)

(note that both "a" and "b" are matrices).

* > B <- NULL
*

> B[[1]] <- a

* > B[[2]] <- b
** > B
*

[[1]]

[,1] [,2] [,3]

[1,] 1 1 1 [2,] 1 1 1 [3,] 1 1 1 [[2]] [,1]

[1,] 1

* >
*

This is fine.

But swapping "a" and "b" over does not behave as desired:

* > B <- NULL
*

> B[[1]] <- b

* > B[[2]] <- a
*

Error in B[[2]] <- a : more elements supplied than there are to replace

* >
*

The error is given because after B[[1]] <- a, the variable B is
just a scalar and

not a matrix (why is this?)

What's the bulletproof method for assigning matrices to a list (whose
length is

not known at runtime)?

-- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743 ______________________________________________ R-help@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 and provide commented, minimal, self-contained, reproducible code.Received on Tue Jan 16 21:30:55 2007

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