[R] strange behaviour with loops and lists

Liviu Andronic landronimirc at gmail.com
Sun May 19 19:10:51 CEST 2013


On Sun, May 19, 2013 at 7:02 PM, peter dalgaard <pdalgd at gmail.com> wrote:
> (The first example really had 2:3, not 5:7, right?)
>
Indeed. I simplified the example mid-email.


> The essential bit is that to assign to the 2nd element of a list, it needs to have at least two elements:
>
Thanks for the explanations. Regards,
Liviu


>> x <- list()
>> x[[2]] <- 123
>> x
> [[1]]
> NULL
>
> [[2]]
> [1] 123
>
> assigning to an element with a specific name just requires there is an element of that name:
>
>> x[["2"]] <- 321
>> x
> [[1]]
> NULL
>
> [[2]]
> [1] 123
>
> $`2`
> [1] 321
>
> In both cases, x will be extended if needed, so that the required element exists. Notice that there is no relation between the name and the number of a list element; e.g., x[["2"]] is the 3rd element in the above example.
>
>
> --
> Peter Dalgaard, Professor,
> Center for Statistics, Copenhagen Business School
> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
> Phone: (+45)38153501
> Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com
>
>
>
>
>
>
>
>



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