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How to find the mean of a matrice based on a value in another matrice

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Hello everyone,
I have two matrices (attached file data_x.mat contains two matrices/parameters) namely 'month' and 'sa'. I want to get, the mean of 'sa' which correspond to values, for example of month = 9 only. Anyone knows how to handle this?
Thanks

Accepted Answer

Star Strider
Star Strider on 8 Oct 2024 at 14:44
This returns all of the monthly means for all the months —
LD = load('data_x.mat')
LD = struct with fields:
month: [125818x1 double] sa: [125818x1 double]
T1 = table(LD.month, LD.sa, 'VariableNames',{'month','sa'})
T1 = 125818x2 table
month sa _____ ______ 9 34.532 9 34.54 9 34.545 9 34.544 9 34.542 9 34.543 9 34.544 9 34.555 9 34.542 9 34.541 9 34.541 9 34.54 9 34.532 9 34.519 9 34.527 9 34.544
[Um,~,ix] = unique(T1.month, 'stable');
mmeans = accumarray(ix, (1:numel(ix)).', [], @(x)mean(T1.sa(x)));
Monthly_Means = table(Um, mmeans, 'VariableNames',{'month','mean'})
Monthly_Means = 12x2 table
month mean _____ ______ 9 34.551 10 34.551 11 34.552 12 34.555 1 34.557 2 34.556 3 34.555 4 34.556 5 34.555 6 34.554 7 34.552 8 34.553
.
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More Answers (1)

Sameer
Sameer on 8 Oct 2024 at 14:42
Edited: Sameer on 8 Oct 2024 at 14:43
Hi Adi
To calculate the mean of 'sa' values corresponding to a specific 'month' (e.g., month = 9), you can follow the below approach:
% Load the data from the .mat file
data = load('data_x.mat');
% Extract the 'month' and 'sa' matrices
month = data.month;
sa = data.sa;
% Find indices where month is equal to 9
indices = find(month == 9);
% Extract the corresponding 'sa' values
sa_selected = sa(indices);
% Calculate the mean
mean_sa = mean(sa_selected);
fprintf('The mean of sa values for month = 9 is: %.2f\n', mean_sa);
I hope this helps!

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