Is the loop getting skipped? I wanted las to take last array of trk with a value in it. but for some the loop seems to get skipped.. What am I doing wrong? Can someone please help??

tk = 1;
trk = { [1;1], [1;1], [1;1], [1;1], [0;0], [0;0], [0;0]};

las =[];
if isempty(las)
    las = [0;0];
    for roll = 7:1
        las = cell2mat(trk{tk,roll});
        if (las(1,1) ~= 0) || (las(2,1) ~= 0)
            break
        end
    end
end

OUTPUT

    las =

         0
         0

    roll =

         []

[Image Analyst]

Original (earlier) version at http://www.mathworks.com/matlabcentral/answers/87176-is-the-loop-getting-skipped-i-wanted-las-to-take-last-array-of-trk-with-a-value-in-it-but-for-some (I answered the first version.)

Answer 1

[dpb]

   for roll = 7:1

Above is equivalent to

   for roll = 7:1:1

what happens when add +1 to 7 and the test for another pass in the loop?

Need the -1 step increment to walk backwards.

[Manoj Kumar Kanakasabapathy]

Thanks dpb!