# append to a table using findgroups and splitapply

2 views (last 30 days)
Qiana Curcuru on 20 Jul 2021
Answered: Simon Chan on 20 Jul 2021
I have a for loop that creates a table every iteration but i just want to append the new data table to the end of the last table that was made instead of over writing the table every iteration. how would i do that?
for i=1:10
a = {...
'apples' 1 2;...
'orange' 2 3;...
'apples' 3 4;...
'Pear' 4 5;...
'apples' 5 6;};
% Extract the first 3 items
a2 = a(1:3,:);
% Apply findgroups
[G, fields] = findgroups(a2(:,1));
% Execute splitapply
x = splitapply(@sum, cell2mat(a2(:,2)), G);
% Summarize the result
tResult = table(fields, x,...
'VariableNames',{'Item','Value'});
% Show the result
disp(tResult)
end

Simon Chan on 20 Jul 2021
Create an empty cell and empty array before the loop.
Then create the table after the loop.
combinefields={}; % Empty cell
combinex = []; % Empty array
for i=1:10
a = {...
'apples' 1 2;...
'orange' 2 3;...
'apples' 3 4;...
'Pear' 4 5;...
'apples' 5 6;};
% Extract the first 3 items
a2 = a(1:3,:);
% Apply findgroups
[G, fields] = findgroups(a2(:,1));
% Execute splitapply
x = splitapply(@sum, cell2mat(a2(:,2)), G);
% Summarize the result
combinefields = vertcat(combinefields, fields); % Combine 'fields'
combinex = [combinex; x]; % Combine 'x'
end
tResult = table(combinefields, combinex,... % Create table after finishing the loop
'VariableNames',{'Item','Value'});
%% Show the result
disp(tResult)

R2018b

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