Re: [R] Getting all possible combinations

> On 24 Aug 2017, at 11:58 , peter dalgaard wrote: > > M <- as.matrix(do.call(expand.grid, rep(list(0:1),5))) > M > # This is just 0:31 encoded as (little-endian) binary > apply(M, 1, function(i) sum((2^(0:4))[i])) > > # now, use rows of M for logical indexing into "A"-"E" >

Re: [R] Getting all possible combinations

> On 24 Aug 2017, at 11:58 , peter dalgaard wrote: > > apply(M, 1, function(i) sum((2^(0:4))[i])) -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email:

Re: [R] Getting all possible combinations

> On 24 Aug 2017, at 01:25 , Duncan Murdoch wrote: > > On 23/08/2017 6:25 PM, Bert Gunter wrote: >> Doesn't sort by size of subgroup. I interpret the phrase I asterisked as: > > You were fooled by Peter's tricky single negative. > ... Let's do this more carefully,

Re: [R] Getting all possible combinations

On 23/08/2017 6:25 PM, Bert Gunter wrote: Doesn't sort by size of subgroup. I interpret the phrase I asterisked as: You were fooled by Peter's tricky single negative. Duncan Murdoch Your code does the following: First subsets of size 1 are given. Then all subsets of size 2. Then all

Re: [R] Getting all possible combinations

Doesn't sort by size of subgroup. I interpret the phrase I asterisked as: Your code does the following: First subsets of size 1 are given. Then all subsets of size 2. Then all subsets of size 3. etc. Your code does not do this (quite). If you meant something else, then please clarify. Cheers,

Re: [R] Getting all possible combinations

> On 23 Aug 2017, at 23:12 , Bert Gunter wrote: > >> 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.

Re: [R] Getting all possible combinations

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 wrote: > >> On 23 Aug 2017, at

Re: [R] Getting all possible combinations

> On 23 Aug 2017, at 20:51 , Ista Zahn wrote: > > On Wed, Aug 23, 2017 at 12:35 PM, Bert Gunter wrote: >> ummm, Ista, it's 2^n. > > ummm yes ug. > You didn't really say otherwise: sum(choose(n,0:n)) == 2^n by the binomial expansion of (1+1)^n

Re: [R] Getting all possible combinations

On Wed, Aug 23, 2017 at 12:35 PM, Bert Gunter wrote: > ummm, Ista, it's 2^n. ummm yes ug. 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 > >

Re: [R] Getting all possible combinations

On 2017-08-23 11:35 AM, Bert Gunter wrote: ummm, Ista, it's 2^n.   or (2^n-1) if the empty set is not considered as a "combination" ;-)  spencer Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus

Re: [R] Getting all possible combinations

ummm, Ista, it's 2^n. 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 wrote: > On

Re: [R] Getting all possible combinations

On Wed, Aug 23, 2017 at 11:33 AM, Christofer Bogaso 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

Re: [R] Getting all possible combinations

Please at least do a basic internet search before posting here. Searching on "R combinations" brought up the combn() function, which you can use in a simple loop to get your answer: > lapply(seq_len(5), FUN = function(x)combn(LETTERS[1:5], x)) ## You can use a for() loop if you prefer [[1]]

Re: [R] Getting all possible combinations

lapply(1:5, function(x) combn(groups, x)) or perhaps unlist(lapply(1:5, function(x) combn(groups, x, FUN = paste, collapse = ", "))) Best, Ista On Wed, Aug 23, 2017 at 11:33 AM, Christofer Bogaso wrote: > Hi again, > > I am exploring if R can help me to get all

[R] Getting all possible combinations

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