Sort a cell array based on average of one cell column/row, then sort the structure

Hi, I have a cell array that contains a number of n by 2 matrices. I want to do the following:

1. determine the averge value of the columns in each matrix.
2. sort the cell array based on the average values of column 1 (or column 2, for another analysis)
3. re-arrange other fields in the structure based on this new order

For example say field 1 is a cell array (1x5 cells) contains matrices: 8x2, 6x2, 9x2, 7x2, 7x2; I want to sort this, then use the order to sort field 2, which contains 5 vectors (a 5x20 matrix), and field 3, which is another cell array 1x5 cells. I hope this makes sense.

Can anyone help thank you very much!

Answer 1

[Ameer Hamza]

See this example

rng(0); % repeatability
A = {rand(8,2), rand(10,2), rand(6,2)}; % example data
A_avg = cellfun(@(x) mean(x(:,1)), A); % get average of first columns
[~,idx] = sort(A_avg);
A_sorted = A(idx);

This arrange the cell array A, using the average of first column, in an ascending order.

[alicia che]

Thank you! This worked great for me and so simple!

[Ameer Hamza]

I am glad to be of help.

Answer 2

[Peng Li]

I thought I answered this question... anyway, this is less clearer than the other one you asked. See example below

% generated a 1 by 5 cell, each with a n*2 random matrix.
% n generated randomly within 1 and 20
ind      = 1:5;
testCell = arrayfun(@(x) rand(randi(20), 2), ind, 'UniformOutput', 0);

% make it a field of a struct
testStruct.field1 = testCell;

% mean of each column within cell
meanInCell = cell2mat(cellfun(@mean, testCell, 'UniformOutput', 0)');
% sort by the mean of first column
[~, indSort] = sort(meanInCell(:, 1));
sortTestCell = testCell(indSort);

% other fields
testStruct.field2 = rand(5, 20);

% I guess you have the same n*2 within each cell of the field3
testStruct.field3 = arrayfun(@(x) rand(randi(20), 2), 1:5, 'UniformOutput', 0);

% sort all fields
sortTestStruct    = structfun(@(x) mySort(x, indSort), testStruct, 'UniformOutput', 0);

function y = mySort(x, indSort)
if size(x, 1) > 1
    y = x(indSort, :);
else
    y = x(indSort);
end
end