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

[Martin Maechler]

>>>>> 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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