[R] Is there a sexy way ...?

[peter dalgaard]

Yes, unsplit() it is. I was messing around with ave() (which can be hammered into submission, sort of).

My overlooking unsplit() is somewhat impressive in view of "svn diff -c 18591"....

-pd

> On 27 Sep 2024, at 17:08 , Martin Maechler <maechler using stat.math.ethz.ch> wrote:
> 
>>>>>> Chris Evans via R-help 
>>>>>>    on Fri, 27 Sep 2024 12:20:47 +0200 writes:
> 
>> Oh glorious!  Thanks Duncan.
>> Fortune cookie nomination!
> 
> I don't  disagree with the nomination -- thank you, Duncan!
> 
> However, please note that I'm sure Rolf's was challenged /
> question was ment to work correctly for all  factors `f`  with
> levels "1", "2", "3".
> 
> Almost all solution were simply assuming that the toy example
> `f` was the real `f`, but that's not realistic.
> 
> Consequently, in my view, the only valid proposition and a very
> nice one, indeed, was  Deepayan's (well, he's "R core", ...) 
> 
>   unsplit(x, f)
> 
> Martin
> 
>> On 27/09/2024 11:13, Duncan Murdoch wrote:
>>> On 2024-09-26 11:55 p.m., Rolf Turner wrote:
>>>> 
>>>> I have (toy example):
>>>> 
>>>> x <- list(`1` = c(7, 13, 1, 4, 10),
>>>>            `2` = c(2, 5,  14, 8, 11),
>>>>            `3` = c(6, 9, 15, 12, 3))
>>>> and
>>>> 
>>>> f <- factor(rep(1:3,5))
>>>> 
>>>> I want to create a vector v of length 15 such that the entries of v,
>>>> corresponding to level l of f are the entries of x[[l]].  I.e. I want
>>>> v to equal
>>>> 
>>>>      c(7, 2, 6, 13, 5, 9, 1, 14, 15, 4, 8, 12, 10, 11, 3)
>>>> 
>>>> I can create v "easily enough", using say, a for-loop.  It seems to me,
>>>> though, that there should be sexier (single command) way of achieving
>>>> the desired result.  However I cannot devise one.
>>>> 
>>> 
>>> Don't you find a for loop's naked display of intention to be sexy?
>>> 
>>> Duncan Murdoch
>>> 
>> -- 
>> Chris Evans (he/him)
>> Visiting Professor, UDLA, Quito, Ecuador & Honorary Professor, 
>> University of Roehampton, London, UK.
>> CORE site: http://www.coresystemtrust.org.uk
>> Other work web site: https://www.psyctc.org/psyctc/
>> Personal site: https://www.psyctc.org/pelerinage2016/
> 
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> 
> ______________________________________________
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
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