Row combination for repeated values

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Maha el 21 de Feb. de 2020
Comentada: Maha el 25 de Feb. de 2020
I have different variables (date, time, lat, lon) and X for different depths, where each column represents n times (number of different depths) the same variable at a different depth, let say 0 m, 100 m, 500 m. Here a more explicit example :
A = [20200101, NaN, NaN, 1200, NaN, NaN, 90, NaN, NaN, 45, NaN, NaN, 2, NaN, NaN; % 0 m
NaN, 20200101, NaN, NaN, 1200, NaN, NaN, 90, NaN, NaN, 45, NaN, NaN, 3, NaN; % 100 m
NaN, NaN, 20200101, NaN, NaN, 1200, NaN, NaN, 90, NaN, NaN, 45, NaN, NaN, 4 ]; % 500 m
How can I keep the repeated band combinations for date, time, latitude and longitude, so my final output would be, for each unique Date / Time / Lat / Lon :
B = [20200101, 1200, 90, 45, 2, 3, 4]; % Date / Time / Lat / Lon / Val 0m / Val100m / Val500m
I was thinking of using a for loop with find
find(A(i,1)==A(:,2) & A(i,1)==A(:,3) etc.)
But I if I have 50 different depths, it will be a lot of combinations. Does anyone has a simpler way in mind ?
  1 comentario
Jon el 21 de Feb. de 2020
I'm not understanding what the columns in your A matrix represent. In particular how come the date appears in a different column in each row. Similarly why does the latitude appear in a different column. It looks like they shift over by 1 column in each succesive row, but I don't know if this is always the case, and what it means.

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Spencer Chen
Spencer Chen el 21 de Feb. de 2020
Now, you were not very clear on your column structure. I understand it as in:
A = [date.depth1, date.depth2 .. date.depthNtime, lat.depth1, lat.depth2, etc.]
% A = row X (depth and Var)
If that's the case, then something like this code would solve you problem:
nrows = size(A,1);
ndepth = 3;
A2 = reshape(A,nrows,ndepth,[]); % A2 = row X depth X Var
B = squeeze(nansum(A2,2));
The crux of it is to use nansum() to combine and ignore values from other depths. So we restructure the matrix so we can use nansum().
  5 comentarios
Maha el 25 de Feb. de 2020
My actual real matrix looks like A1, from my previous message, with 500k lines, and 10 different depths.
I need the B matrix as a result (every depth information for unique spatial and temporal information).
The solution I've shown just work for a consistent matrix A2, where each line would represent a depth. My A1 / True matrix isn't consistent.
I would like to either
1) switch from A1 to A2, then I could apply my previous solution
2) Find a direct solution to transform A1 into B

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