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Teemu

How to pick next value from vectors?

Asked by Teemu
on 4 Mar 2013

I have a cumulative vector, size is about 200. I want to pick up that index where value is 0,5 or value which is next to it. For example (0.1, 0.23, 0.42, 0.49, 0.52, 0.56,...), so i want to pick up index which corresponding to value 0.52. How can I do it?

  3 Comments

Jan Simon
on 4 Mar 2013

Does "next" mean the next larger element or the element with the minimal distance? In the 2nd case, the answer would be 0.49, in opposite to your example.

Teemu
on 5 Mar 2013

Minimal distance, in this case it will be 0.49

Teemu
on 5 Mar 2013

actually I need both

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3 Answers

Answer by Jos (10584)
on 4 Mar 2013
 Accepted answer

Here is one approach:

   v = [0.1 0.23 0.4 0.52 0.56 1.1]
   idx = find(v >= 0.5,1,'first')
   v(idx)

  8 Comments

Teemu
on 5 Mar 2013

So how can I do minimal distance pick?

Jan Simon
on 5 Mar 2013

Please, Teemu, read my answer below. There you find the code to pick the element with the minimal distance. It is the 2nd line and the index is the 2nd output of min(abs(v - 0.5)).

Teemu
on 5 Mar 2013

Sorry I didn't noticed that, I thought it was answer for next index. Thanks for your patience.


Answer by Jos (10584)
on 5 Mar 2013

To do this for multiple values, take a look at my function NEARESTPOINT:

http://www.mathworks.com/matlabcentral/fileexchange/8939

  0 Comments


Answer by Jan Simon
on 4 Mar 2013
Edited by Jan Simon
on 5 Mar 2013
v                = [0.1 0.23 0.4 0.52 0.56 1.1];
[absdist, nearest] = min(abs(v - 0.5));  % **SOLUTION IS HERE** !!!
if absdist == 0  % or: <= eps(v(index))
  following = index;
else
  following = index + 1;
end
nearestValue   = value(nearest);
followingValue = value(following);

  0 Comments


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