Start Cumsum from table of values that correspond with given indeces

Hello, I have a timetable of values called ddtable with column 'RAIN' and an array of index called startdd.

The objective:

1) If index of ddtable matches with startdd, start cumsum for subsequent RAIN values until it exceeds 3.5 then stop.

2) Append all indices that were involved in the cumsum into a new table

How do I go about this because traditional while loop does not work as well and no discussion have addressed this type of question.

for ii = 1:length(rain)
%  If rain index matches with startdd, start cumulation
   if idx(rain) == startdd
       %  The cumulation will end once it exceeds 3.5mm
       while cumsum(rain(startdd)) < 3.5
%            Append all index values that were involved in the cumsum
       end
   end
end

Many thanks!

[Eric Sofen]

The data in your MAT files doesn't match up with your example code, so I'm not 100% sure what you're trying to do, but see if this does the trick.

load('ddtable.mat')
load('startdd.mat')
result =ddtable([],:);
inds = [];
for ii = startdd % Iterate over start indices
    cs = cumsum(ddtable.RAIN(ii:end)); %do cumsum over most of the rain data - we'll end up throwing away anything beyond 3.5 mm
    inds3_5 = ii-1 + find(cs <= 3.5); % Find where data is below the 3.5mm threshold; adjust based on the start index.
    result = [result; ddtable(inds3_5,:)]; % append data
    inds = [inds; inds3_5]; % append indices
end

[Jonathan Cheong]

Wow! Thank you very much Eric this is exactly what I was looking for.

However, after studying the results another condition that I thought I had eliminated beforehand emerged.

Condition: The cumsum cannot be less than 4 days.

So for example, there are 3 cumsum instances:

A) 15

B) 60, 61, 62, 63...

C) 70, 72

How do I remove A and C but not B from the result?

Ps: If I have to start a new question let me know.