Selection of priority data

Hello,

I'm trying to solve a problem. I have a vector of data such as:

data=[3;4;8;NaN;NaN;NaN;7;4;3;NaN;NaN;2;3;NaN;9]

length of data can be variable and NaN value phases can happen everywhere within a vector.

I need to find the first NaN value and count the number of next NaN. However, I do not want to take into account any other NaN value after the first portion of NaN.

In this case my result would be: First NaN at raw 4. Three NaN values. I know how to use the function find, indeed this is the code I used as far:

findNaN = find(isnan(data));

The problem is that in that way I will get the others NaN too that I do not want to locate.

Any idea?

Thanks, Giuseppe

Answer 1

[Shoaibur Rahman]

    data=[3;4;8;NaN;NaN;NaN;7;4;3;NaN;NaN;2;3;NaN;9];
    findNaN = find(isnan(data));

    first = findNaN(1);
    numberNaN = 1;
    for k = first+1:length(data)
        if isnan(data(k))
            numberNaN = numberNaN+1;
        else break
        end
    end

    first, numberNaN

Answer 2

[Image Analyst]

If you're lucky enough to own the Image Processing Toolbox, it's easy. Just find the nan's, label then, and count the number in the first group. Here is the code:

labeledVector = bwlabel(isnan(data)) % Find nan's and label.
numberOfNansInFirstGroup = sum(labeledVector == 1) % Count the # of elements in group #1

Answer 3

[Giuseppe]

thanks for helping to improve my code