How to do operations on nested cell array?

I have a nested cell array named 'events'.Each cell contains either 1 or more than 1 cells which in turn contains time series.

I want to write a code where, if the cell contains more than 1 cell arrays of time series, I want to find the standard deviation of each of those time series and retain only the time series with the highest standard deviation.

For ex: For the case of events {6,1} which contains 3 time series, I want to find the std of events{6,1}{1,1}, events{6,1}{2,1} and events{6,1}{3,1} and only retain the time series with the highest std and delete the rest.

How can I do this?

Thanks

Answer 1

[Walter Roberson]

for K = 1 : numel(events)
  [~, idx] = max(cellfun(@std, events{K}));
  Events{K} = events{K}(idx);
end

I would not bother trying to do it without a loop. It is possible, yes, but avoiding the loop requires calculating the std twice because inside the loop it is not possible to get at the second output of max()

[maruljay]

I get the error:

Error using cellfun

Input #2 expected to be a cell array, was double instead.

Answer 2

[Turlough Hughes]

This should hopefully work but i ament able to test it myself right now as I'm away from my computer. The idea is to pass onecell at a time from the first level through a subfunction called myfun. myfun subsequently uses cellfun again to check each subcell, it finds the one with max standard deviation and should return that one.

EventsStdMax = cellfun(@(x) myfun(x),events,'UniformOutput',false)

function out = myfun(onecell)
[~,idx] = max(cellfun(@(x) std(x), onecell));
out = onecell{idx};
end

Edit: As Walter pointed out.

[Walter Roberson]

out = subcell{idx};

should probably be

out = onecell{idx};

[Turlough Hughes]

Thanks.

[maruljay]

I get the error:

Error using cellfun

Input #2 expected to be a cell array, was double instead.

[Walter Roberson]

Your screen snapshot shows the entries in events are cell arrays, but one of the entries between 28 and 58 is not a cell array (possibly it is unexpectedly [] instead of {})

[maruljay]

Or is it because the time series is stored as a double like the screenshot shows 1x4217 double?

[Walter Roberson]

No, according to your images , the first 27 entries in events are not timeseries and are instead cell arrays containing timeseries. But somewhere in events you have an entry which is not a cell array.

cellfun(@class, events, 'uniform', 0)

and look for one that does not say 'cell'