Inline. -- Bert Bert Gunter
"The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Wed, Aug 23, 2017 at 1:58 PM, peter dalgaard <pda...@gmail.com> wrote: > >> On 23 Aug 2017, at 20:51 , Ista Zahn <istaz...@gmail.com> wrote: >> >> On Wed, Aug 23, 2017 at 12:35 PM, Bert Gunter <bgunter.4...@gmail.com> wrote: >>> ummm, Ista, it's 2^n. >> >> ummm yes ughhhh. >> > > You didn't really say otherwise: sum(choose(n,0:n)) == 2^n by the binomial > expansion of (1+1)^n (but you knew that) > > This points to a different algorithm where you write 0:(2^n-1) as n-digit > binary numbers and chose items corresponding to the 1s. That won't give the > combinations **sorted by size of selected subgroup** though. Something like > this: No it doesn't. -- Bert > > M <- as.matrix(do.call(expand.grid, rep(list(0:1),5))) > mode(M) <- "logical" > apply(M,1,function(i)LETTERS[1:5][i]) > > -pd > > >> My point is, if the number of groups is large, check it before hand. >> If you can check it without embarrassing yourself in public like I did >> that's even better. >> >> Best, >> Ista >> >>> >>> Cheers, >>> Bert >>> >>> >>> Bert Gunter >>> >>> "The trouble with having an open mind is that people keep coming along >>> and sticking things into it." >>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) >>> >>> >>> On Wed, Aug 23, 2017 at 8:52 AM, Ista Zahn <istaz...@gmail.com> wrote: >>>> On Wed, Aug 23, 2017 at 11:33 AM, Christofer Bogaso >>>> <bogaso.christo...@gmail.com> wrote: >>>>> Hi again, >>>>> >>>>> I am exploring if R can help me to get all possible combinations of >>>>> members in a group. >>>>> >>>>> Let say I have a group with 5 members : A, B, C, D, E >>>>> >>>>> Now I want to generate all possible unique combinations with all >>>>> possible lengths from that group e.g. >>>>> >>>>> 1st combination : A >>>>> 2nd combination : B >>>>> ..... >>>>> 5th combination : E >>>>> 6th combination : A, B >>>>> 7th combination : B, C >>>>> .... >>>>> last combination: A, B, C, D, E >>>>> >>>>> Ideally, I have a fairly large group so am looking for some >>>>> programmatic way to generate all possible combinations. >>>> >>>> Be careful, the number of combinations grows pretty quickly. You can >>>> calculate the number ahead of time with >>>> >>>> sum(choose(n, 1:n)) >>>> >>>> where n is the number of values in your group. >>>> >>>> --Ista >>>> >>>>> >>>>> Any help will be highly appreciated. >>>>> >>>>> Thanks for your time. >>>>> >>>>> ______________________________________________ >>>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >>>>> https://stat.ethz.ch/mailman/listinfo/r-help >>>>> PLEASE do read the posting guide >>>>> http://www.R-project.org/posting-guide.html >>>>> and provide commented, minimal, self-contained, reproducible code. >>>> >>>> ______________________________________________ >>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >>>> https://stat.ethz.ch/mailman/listinfo/r-help >>>> PLEASE do read the posting guide >>>> http://www.R-project.org/posting-guide.html >>>> and provide commented, minimal, self-contained, reproducible code. >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > -- > Peter Dalgaard, Professor, > Center for Statistics, Copenhagen Business School > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > Phone: (+45)38153501 > Office: A 4.23 > Email: pd....@cbs.dk Priv: pda...@gmail.com > > > > > > > > > ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
