How to pick next value from vectors?

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?

[Jan]

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]

Minimal distance, in this case it will be 0.49

[Teemu]

actually I need both

Answer 1

[Jos (10584)]

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)

[Wayne King]

@Jos, You're absolutely right Jos, I misread the poster's question. My answer is not relevant, deleting.

[Jan]

The new version of your answer is the most clean and efficient solution. +1

(or "cleanest and most efficient"?)

[Teemu]

It works fine, thanks. I have one extra question; can I pick value which is closest to value 0.5?

[Teemu]

I mean can I pick index which value is closest to 0.5?

[Jan]

@Teemu: See index in the code I've posted yesterday already.

[Teemu]

So how can I do minimal distance pick?

[Jan]

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]

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

Answer 2

[Jos (10584)]

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

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

Answer 3

[Jan]

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);

[shariq khan]

what if I need next larger value? consider same data but my value at specific index is nil (or no value from dataset) but now I want to find if there is any value next to that specific value in the dataset

[shariq khan]

I think I found answer to my problem

Problem - all vectors are of same length

x = [some values]

t = [some values]

x1 = 0.9*max(x);

find t value that corresponds to x1 value

if not find the closest value

solution : A lot from @jan ans

[answer,index] = min(abs(x - x1))

t1(that is to be determined) = t(index);

I hope it helps to solve people facing specific problem