I want to know the starting index of consecutive negative elements and also thier count.

I just have an array of 76140 data. What to do, if I want to know the starting index of consecutive negative elements and also thier count. Thank you in advance

[Rik]

Good for you. Do you also have a question? Have you tried anything?

The RunLength FEX submission may be helpful.

Answer 1

[Matt J]

Using this File Exchange submission,

https://www.mathworks.com/matlabcentral/fileexchange/78008-tools-for-processing-consecutive-element-groups-in-vectors

yourVector = [0 -3 -4 1 2 7 -9 -10 -11]; %example

G=groupTrue(yourVector<0);

startingIndex  = groupFcn(@(x) x(1)    , 1:numel(G), G),

startingIndex = 1×2

2 7

count = groupFcn(@numel , G, G),

count = 1×2

2 3