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How to generate sequences from two vectors using rowfun

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Etsuko
Etsuko on 13 Jul 2016
Edited: Stephen on 13 Jul 2016
Hi,
I am trying to generate sequences for which starting values and last values+1 are contained in vectors, without using for-loop. Because there is a lot of data to process, doing for-loop is unfortunately not feasible. As the output, I want to have all the sequences to be concatenated into one vector. I think rowfun can help me here, but so far I have not been successful. If someone can give me a helping hand, I would be grateful.
This is an example;
x = [1,6,12]'; y = [5,10,13]';
the output I wish to obtain: z = [1,2,3,4,6,7,8,9,12];
I imagine it should be something like;
inputvecs = table(x,y);
z = rowfun(@seqgen,inputvecs)
How should the function seqgen look in this case? Should concatenation within the function?
Thank you very much for your help.
Etsuko

Accepted Answer

Stephen
Stephen on 13 Jul 2016
Edited: Stephen on 13 Jul 2016
You could use arrayfun instead:
>> x = [1,6,12]; y = [5,10,13];
>> cell2mat(arrayfun(@(a,b)a:b-1, x,y,'UniformOutput',false))
ans =
1 2 3 4 6 7 8 9 12
or
>> tmp = arrayfun(@(a,b)a:b-1,x,y,'UniformOutput',false);
>> horzcat(tmp{:})
ans =
1 2 3 4 6 7 8 9 12
Note that the inputs must be horizontal vectors.
  2 Comments
Stephen
Stephen on 13 Jul 2016
@Etsuko: note that to get meaningful timing values for such quick functions, it is recommended to repeat the process a few hundred or thousand times.

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More Answers (1)

Andrei Bobrov
Andrei Bobrov on 13 Jul 2016
Edited: Andrei Bobrov on 13 Jul 2016
x = [1,6,12]; y = [5,10,13];
a = (min(x):max(y))';
[ii,~] = find(bsxfun(@ge,a,x)&bsxfun(@lt,a,y));
out = a(ii);

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