[Rd] Add on argument in seq()

[Gabriel Becker]

Millot,

On Mon, Jun 15, 2015 at 9:19 AM, Hadley Wickham <h.wickham at gmail.com> wrote:

> Regardless of the value of the other arguments, the first element in
> the output of seq() is _always_ `from`.
>


Indeed, as Hadley says, the output of seq must always start with* from*. It
is a sequence starting at *from* and ending wherever the other arguments
cause it to end. A sequence starting at* from *of length one is simply that
single value. That is the contract I was referring to in my previous email.
Apologies if that was not clear.

If that isn't the behavior you want when length.out  ends up being 1, your
code will need to protect against that scenario.

I could see the argument for it being a warning/error if from and to are
both specified and length.out is one, as a (lesser) part of the contract is
that the last element of seq should be to, but even though it might make
sense I really don't see that change going in. If I were you I'd just add
an if statement in my function to check if length.out is 1 and move on.

Best,
~G


>
> Hadley
>
> On Mon, Jun 15, 2015 at 9:56 AM, Millot Gael <Gael.Millot at curie.fr> wrote:
> > Thanks for your answer.
> >
> > The rational behind my proposal is why taking "from" when length.out=1,
> more than "to" or "NA", or " integer(0) " ?
> >
> > This question seems basic. But is is not in certain situations, like
> when length.out =  unpredictable positive integer.
> > And I haven't found in ?seq() the particular behavior of this function
> when length.out = 1.
> >
> > Thanks for your help !
> >
> > Best,
> >
> > Gael.
> >
> >
> > De : Gabriel Becker [mailto:gmbecker at ucdavis.edu]
> > Envoyé : lundi 15 juin 2015 16:25
> > À : Millot Gael
> > Cc : r-devel
> > Objet : Re: [Rd] Add on argument in seq()
> >
> >
> > Millot,
> >
> > I think the problem with that is that what you propose isn't a sequence
> starting  at from in any meaningful way, and thus does not satisfy the
> contract of the seq function.
> >
> > Best,
> > ~G
> > On Jun 15, 2015 7:12 AM, "Millot Gael" <Gael.Millot at curie.fr<mailto:
> Gael.Millot at curie.fr>> wrote:
> > Hi.
> >
> > I have a problem with the default behavior of seq(), which gives the
> argument "from" when the argument length.out = 1.
> > This behavior is annoying when the number of value determine in
> length.out is not predictable.
> > Would it be possible to add an argument that propose the median/mean,
> i.e. (from + to) / 2 when  length.out = 1 ? Examples:
> >> seq(from = 1, to =  11, length.out=1) # current method gives "from"
> > 1
> >
> >> seq(from = 1, to =  11, length.out=1) # alternative method gives the
> intermediate value of "from" and "to"
> > 6
> >
> > Many thanks for your help.
> >
> > Best wishes,
> >
> > Gael Millot.
> >
> >
> > Gael Millot
> > UMR 3244 (IC-CNRS-UPMC) et Universite Pierre et Marie Curie
> > Equipe Recombinaison et instabilite genetique
> > Pav Trouillet Rossignol 5eme etage
> > Institut Curie
> > 26 rue d'Ulm
> > 75248 Paris Cedex 05
> > FRANCE
> > tel : 33 1 56 24 66 34
> > fax : 33 1 56 24 66 44
> > Email : gael.millot at curie.fr<mailto:gael.millot at curie.fr>
> > http://perso.curie.fr/Gael.Millot/index.html
> >
> >
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> >
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>
>
> --
> http://had.co.nz/
>



-- 
Gabriel Becker, PhD
Computational Biologist
Bioinformatics and Computational Biology
Genentech, Inc.

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