Average across structures and fields

Hello, I currently have a set of data that is organized into a main structure with 3 fields (walking_01, walking_02, walking_03). Each of those 3 fields has a sub-structure with 101 fields (LHipAngles, LKneeAngles, etc.). Each of these 101 fields are made up of a double array containing 101 rows x any number of columns. I would like to find the average of each of the 101 fields across all of the main structure's fields (i.e. average of LHipAngles across walking_01, walking_02, and walking_03).

Answer 1

[Jan]

It was a bad idea to hide an index in the field names as in walking_01. Using an array with a real index is smarter. This is fixed easily:

ModOutLStride_x.walking = cat(1, ModOutLStride_x.walking_01, ...
                                 ModOutLStride_x.walking_02, ...
                                 ModOutLStride_x.walking_03));

By the way, the "L" in the name of the structure looks like you hide the information about the side in the name of the variable. The code is more flexible, if you store the side information separately.

After the above creation of the array:

Data    = ModOutLStride_x;  % Abbreviation
keyList = fieldnames(Data.walking(1));
nCycle  = numel(Data.walking);
for iKey = 1:numel(keyList)
    key   = keyList{iKey};
    value = 0;
    for iCycle = 1:nCycle
        value = value + Data.walking(iCycle).(key);
    end
    Data.mean.(key) = value / nCycle;
end

[Josh Tome]

Thank you. I was able to get this to work but I've changed my approach on how I'd like to process this data. I instead would like to merge each variable (i.e. LHipAngles) across all walking trials (walking_01, walking_02, and walking_03), and then take the average. This will allow me to export all of the individual arrays so that I can inspect them later and remove outliers.

I know this can be done using the code below, but I just need to figure out how to write it into a for loop for each variable across each trial

horzcat(ModOutLstride_x.walking_01.LHipAngles,ModOutLstride_x.walking_02.LHipAngles,ModOutLstride_x.walking_03.LHipAngles)

[Jan]

My code sums up these variables, and you want to concatenate them. So you can modify my code easily:

...
    valueC = cell(1, nCycle);
    for iCycle = 1:nCycle
        valueC{iCycle} = Data.walking(iCycle).(key);
    end
    Data.All.(key) = cat(2, valueC{:});  % Or maybe cat along 1st or 3rd dim?
...