Conditional Indexing of a cumsum

From a random data k, I would like to fulfill 2 Conditions:

1) Cumsum until 3.5mm - Fulfilled

2) Each cumsum interval must be more than 4 index

Below is the code:

clean = k([],:);
indclean = [];
k =  rand(1000,1);
for ii = startind % Iterate over start indices
    cs = cumsum(k(ii:end));
    inds3_5 = ii-1 + find(cs <= 1); % Find where data is below the 3.5mm threshold; adjust based on the start index.
    clean = [clean;k(inds3_5,:)]; % append data
    indclean = [indclean; inds3_5]; % append indices
end

Hence, how do I make it so that only cumsum that last more than 4 indexes are used.

Many thanks.

Answer 1

[Asvin Kumar]

Store find(cs<=1) in a temporary variable and count the number of elements in that list.

tmp = find(cs<=1);
if numel(tmp)>=4
    % your code here
end

[Jonathan Cheong]

Thank you very much! This is exactly what I was looking for.