Path: news.mathworks.com!not-for-mail From: <HIDDEN> Newsgroups: comp.soft-sys.matlab Subject: Re: Finding end-points for runs Date: Sun, 27 Jan 2013 06:23:08 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 39 Message-ID: <ke2h4c$dju$1@newscl01ah.mathworks.com> References: <cd7ccb2d-8c83-4568-a565-22f22a9416bf@googlegroups.com> Reply-To: <HIDDEN> NNTP-Posting-Host: www-05-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: newscl01ah.mathworks.com 1359267788 13950 172.30.248.37 (27 Jan 2013 06:23:08 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Sun, 27 Jan 2013 06:23:08 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1187260 Xref: news.mathworks.com comp.soft-sys.matlab:787471 Gautam Sethi <gautamsethi@gmail.com> wrote in message <cd7ccb2d-8c83-4568-a565-22f22a9416bf@googlegroups.com>... > Dear all: > I'm trying to find the end-points for runs of numbers based on a vector. Let > > >> Y = [1 3 4 6 7 8] > > Y = > > 1 3 4 6 7 8 > > I want an output vector Z of size(length(Y),2) where > > Z = > > 0 2 > 2 5 > 2 5 > 5 9 > 5 9 > 5 9 > > Here is the idea behind what I want. > > The first element of Y is 1, which is not followed by the next integer; thus, the integers that "surround" the integer 1 are 0 and 2, the first row of Z. > > The second element of Y is 3, which is followed by the next integer, 4. However there is a break after 4. Thus, the run of consecutive integers 3 and 4 is "surrounded" by the integers 2 and 5. Therefore, the next two rows of Z, corresponding to the two elements 3 and 4 of Y, are [2 5]. > > Likewise, the last three elements of Y are consecutive integers, "surrounded" by the integers 5 and 9. Hence the last three rows of Z are [5 9]. > > Thanks for your help! - - - - - - - - - Y = Y'; f = find([true;diff(Y)>1;true]); Z = zeros(size(Y,1),2); Z(1,:) = [Y(1)-1,Y(f(2)-1)+1]; Z(f(2:end-1),:) = diff([Y(f(1:end-1)),Y(f(2:end)-1)],1,1); Z = cumsum(Z,1); Roger Stafford