How do I take an average of fields in a structure?
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Liz Web
le 23 Mar 2018
Réponse apportée : George Abrahams
le 30 Déc 2022
I have 3 fields in a structure that I want to take the average and standard deviation of. What is the simplest way to do this?
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/171515/image.png)
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Image Analyst
le 24 Mar 2018
One way
totalMean = mean([BindingDataToSave.TotalVirusesBound]);
totalStdDev = std([BindingDataToSave.TotalVirusesBound]);
Similar for the other 2 fields. Walter's method is probably better since it gives you all 3 means in one shot.
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Plus de réponses (2)
Walter Roberson
le 24 Mar 2018
means = structfun(@mean, BindingDataToSave, 'uniform', 0);
stds = structfun(@std, BindingDataToSave, 'uniform', 0);
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George Abrahams
le 30 Déc 2022
An improvement over Walter's answer would be to use my fieldfun function on File Exchange / GitHub, which outputs a structure with the same fields as the input structure(s). That means that you can index the means and standard deviations without knowing the order of the fields (effectively columns in your attached image).
rng(1,'twister')
BindingDataToSave = struct( 'TotalVirusesBound', num2cell(rand(26,1)), ...
'NumberGoodViruses', num2cell(rand(26,1)), 'NumberBadViruses', ...
num2cell(rand(26,1)) );
fieldfun( @(varargin) mean([varargin{:}]), BindingDataToSave )
% ans = struct with fields:
% TotalVirusesBound: 0.4574
% NumberGoodViruses: 0.4675
% NumberBadViruses: 0.4530
Although, you should probably also consider using a table and not a structure.
BindingDataToSave = struct2table( BindingDataToSave );
mean( BindingDataToSave.TotalVirusesBound )
% ans = 0.4574
varfun(@mean,BindingDataToSave)
% ans = 1×3 table
% mean_TotalVirusesBound mean_NumberGoodViruses mean_NumberBadViruses
% 0.45736 0.46752 0.45302
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