Thank you all for clarifying that bug in my understanding! I suppose
that I expected 'a' to be promoted to a list when indexed from NULL.
I will be more judicious in the future when I post.
Daniel Wilhelm
>On Mon, 16 Jul 2007, Daniel Wilhelm wrote:
>
>>I believe that I may have found a bug in R. The top code sample gives
>
>You have 'merely' found a bug in your understanding. What type did
>you expect 'a' to be? If you expected a list, that is not what
>happens in the first example, and you need
>
>a <- list()
>
>or, better,
>
>a <- vector("list", 2)
>
>>an error as shown. However, by simply switching which field is
>>initialized first as in the bottom code sample, it works as expected.
>>
>>
>>This gives an error:
>>
>>
>>a <- NULL
>>a[["field1"]] <- 1
>
>Now a is numeric
>
>>a[["field2"]] <- matrix(c(2,1), 1)
>>
>>Error in a[["field2"]] <- matrix(c(2, 1), 1) :
>> more elements supplied than there are to replace
>>
>>
>>
>>Yet, this works as expected:
>>
>>a <- NULL
>>a[["field2"]] <- matrix(c(2,1), 1)
>
>Now a is a list
>
>>a[["field1"]] <- 1
>>
>>
>>
>>Daniel Wilhelm
>>
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>
>--
>Brian D. Ripley, [EMAIL PROTECTED]
>Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
>University of Oxford, Tel: +44 1865 272861 (self)
>1 South Parks Road, +44 1865 272866 (PA)
>Oxford OX1 3TG, UK Fax: +44 1865 272595
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