Cannot vertically concatenate tables in for loop

Hello experts,

I have an elementary, yet unsolvable issue for me. I checked other questions, I checked the material on the official site but I cannot solve my problem.

I have a 1x1 structure named "tbl" with 17 fields. Each field is a Nx5 table.

I would like to take each table and append that table to the previous one to obtain an Nx5 table, where N is the total number of rows from all the tables.

To append one to the other I know I can do this:

total = [tbl.ID2; tbl.ID4];

But I'd rather do it in a for loop, since I'll add further IDs and it's going to be quite time consuming.

resulting_tbl = table;

for id = tbl
    resulting_tbl = [id;];
end

this code above is just creating the same initial structure instead of a new resulting table.

I know I'm missing some basic notions, but I cannot overtake this problem.

Thank you all for your time and help!

Marco

[KSSV]

Read about join.

[NMarco]

Thank you @KSSV for your suggestion.

Of course I read about join but I'm definetly missing something because I'm not able to acheive what I'm trying to do. I'm getting error that they should be arrays or vectors to be joined together.

What am I missing here?

resulting_tbl = table;
for id = tbl
    resulting_tbl = [id;]; % join here?
end

Thank you!

[Stephen23]

@Marco Ninghetto: having lots of numbered fields is not very good data design. It would be better to use a non-scalar structure or even just a simple cell array.

[NMarco]

@Stephen Cobeldick, so I will probably change the names. I used them as they are because it's easier to trace back to which participant belongs that specific table.

Answer 1

[Walter Roberson]

temp = struct2cell(tbl);
resulting_tbl = vertcat(temp{:});

[NMarco]

I tried that, but unfortunately:

    Error using vertcat
    Dimensions of arrays being concatenated are not consistent.

all the tables have different lenght.

[Walter Roberson]

The image you posted showed all tables as having different heights but all of them had 5 variables. Are there non-empty entries that have a different number of variables?

temp = struct2cell(tbl);
wids = cellfun(@(C) size(C,2), temp);
[uwids, ~, uidx] = unique(wids);
counts = accumarray(uidx(:), 1);
[~, maxidx] = max(counts);
report_table = [counts, uwids];
report_table(maxidx,:) = [];
if isempty(report_table)
    fprintf('Congrats! All cells have %d variables!\n', uwids(1));
else
    fprintf('Opps! Not all cells have the same number of variables! Uncommon ones:\n');
    fprintf('%d cells have %d variables\n', report_table.');
end

[NMarco]

Well, my bad. In the fifth column (should be group variable), some of the tables have a different format from the others. That's why it wasn't working. I fixed it.

The method:

temp = struct2cell(tbl);
resulting_tbl = vertcat(temp{:});

worked perfectly. Thanks!