Set of indexes to vector without loop?

Hi, the problem is as follow:

There is matrix with indexes:

 IND =

           1          15
          26          40
          51          65

I would like to create vector which looks like:

VEC = [1,2,...14,15,26,27,...39,40,51,52...64,65]

For that specific example answer is:

VEC = [1:15, 26:40, 51:65]

but I would like to find general solution without looping. It should be independent from number of rows in in IND.

I didn't find any solution in Matlab answers but I am sure that is possible.

Any ideas? Best Kamil

Answer 1

[Guillaume]

A for loop as per KSSV's answer is probably the best way to do this.

cell2mat(arrayfun(@(s,e) s:e, IND(:, 1), IND(:, 2), 'UniformOutput', false)')

would be one way to do it without a loop, if you consider arrayfun not to be a loop. It's more likely to be slower than an actual for loop.

See also my old cody problem which asks to do just the same. For information, the best scoring solution is:

str2num(sprintf('%d:%d ', IND'))

whose only merit is that it is low scoring on cody. Certainly don't use that for real code, it's going to be very slow.

Answer 2

[KSSV]

iwant = [] ;
for i = 1:size(IND,1)
    iwant = [iwant   IND(i,1):IND(i,2)] ;
end

A more elegant solution might be possible.

[Kamil Antos]

Hi KSSV, thank you for answer. This is what I use so far. I would like to get rid of loop.

[KSSV]

Read this link for the similar question.

https://in.mathworks.com/matlabcentral/newsreader/view_thread/270454