Average over duplicate values in xlsx file

This is my first time using MATLAB so I have very very less knowledge of the syntax. I am stuck with a problem. I have a xlsx file which looks like:
I want to average the columns `Response`, `ResponseC`, `ResponseCo` and `Reaction_time` for repeating values of `StimuliName` and finally in the output have something like this:
Untitled.png
So basically I want the average values with only specific fields.
Can someone please guide me as to how I can get this result?

3 Comments

Adam Danz
Adam Danz on 1 Apr 2019
Edited: Adam Danz on 1 Apr 2019
Are the data already loaded into matlab? If yes, are they stored in one large cell array without the headers or are they stored in a table or a structure?
They are stored in a cell array with the headers.
OK; I added a comment under my answer. Let me know if you get stuck implementing the solution.

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Answers (2)

You can use findgroups() to split the rows into groups based on StimuliName. Then you can use splitapply() to apply a funciton (ie, mean) to a column of the data for each group.
% assign group numbers to simuli names in column 6
[stimGroups, groupID] = findgroups(data(:,6));
% Use splitapply() to perform stats on grouped data in columns 14, 15, and 16
meanVals1 = splitapply(@mean, [data{:, 14}]', stimGroups);
meanVals2 = splitapply(@mean, [data{:, 15}]', stimGroups);
meanVals3 = splitapply(@mean, [data{:, 16}]', stimGroups);
From here you can store the data in a table or cell array. The best choice depends on what format the data are already stored in matlab and how you plan on using the data.

1 Comment

If the cell array contains headers along the first row, you can easily adapt the code above to ignore the first row.
data(:, 6)
% should become
data(2:end, 6)

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T = readtable('yourfile.xlsx');
T_out1 = varfun(@(x)x(1),T,'I',1:14,'G','StimuliName');
T_out2 = varfun(@mean,T,'I',15:18,'G','StimuliName');
out = [T_out1(:,3:end), T_out2(:,3:end)];

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R2017a

Asked:

on 1 Apr 2019

Answered:

on 2 Apr 2019

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