Split table into Chunks.

2022 10 25
2 个回答
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更新时间：2022 10 30
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Hi, I have a large table. I want to split the table into multiple chunks via loop and save its result in workspace so that later I can add into the powepoint slides in Matlab. But the subtables stores in .mat file. I want to save them into workspace as a table.
how can I do it. Any help would be great.
Thanks
I have written the following code:
T = T_measfine;
chunkSize = 8; % chunk size from number of rows
noOfChunks = ceil(size(T,1) / chunkSize)
% %% To Output chunks
for idx = 1:noOfChunks
if idx == noOfChunks
subtable = T(1:end,:)
else
subtable = T(1:chunkSize,:)
savefile = strcat('subdata',num2str(idx));
save(savefile, 'subtable')
end
end

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Walter Roberson
Walter Roberson 2022-10-25
You want to create a table object whose variable contains rows, each of which is a table itself?
Or you want to dynamically create new variables in the workspace, each of which stores one of the subtables?
Saria Ahmad
Saria Ahmad 2022-10-25
I want to create new variables in the workspace.each of which stores one of the subtables.
I have multiple tables and I need to do this in a loop for every table.
Walter Roberson
Walter Roberson 2022-10-25
Why do you need separate named variables? The process for adding information to PowerPoint slides involves calls that pass data by value not by variable name.
Saria Ahmad
Saria Ahmad 2022-10-25
the reason behind this: sometimes the resultant tables becomes very large and when I get the automated result file that large table doesn't fit to the slide. So Idea is to split the tables and then add them to slides.
Walter Roberson
Walter Roberson 2022-10-25
yes but how does that require that different variables be used for each table? Instead of having a cell array of tables for example?

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 采纳的回答

Askic V
Askic V 2022-10-25
Ran in:

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Ran in:
Hello,
you're probably want something like this:
T = randi(10, 43,3);
chunkSize = 8; % chunk size from number of rows
noOfChunks = ceil(size(T,1) / chunkSize);
[rows, col] = size(T);
start_idx = 0;
for idx = 1:noOfChunks
if idx == noOfChunks
endpoint = rows;
else
endpoint = start_idx + chunkSize;
end
eval(sprintf('subTable%d = T(%d:endpoint,:)', idx, start_idx+1));
start_idx = chunkSize*idx;
end
subTable1 = 8×3
10 5 7 5 9 3 1 6 1 6 2 1 1 6 8 10 7 7 5 5 10 5 6 5
subTable2 = 8×3
2 2 2 5 9 2 5 10 6 3 6 1 4 2 8 6 9 10 3 6 6 3 2 10
subTable3 = 8×3
7 3 8 1 3 3 4 4 8 8 6 4 1 3 3 6 6 8 6 4 10 6 6 7
subTable4 = 8×3
7 7 9 8 3 6 10 8 10 6 10 5 7 1 6 10 5 2 9 1 9 9 9 10
subTable5 = 8×3
2 4 8 6 10 1 9 7 6 8 6 10 1 6 2 3 4 3 7 6 7 8 4 4
subTable6 = 3×3
5 9 6 6 5 3 10 8 7
If this is what you want, I need to warn you that this practice is highly unrecommended. YMATLAB arrays (for example cell) will let you do the same thing in a much faster, much more readable way.

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Saria Ahmad
Saria Ahmad 2022-10-25
Thanks, Yes. This is what I want.
How can adapt in matlab arrays? Then I also have to adapt that subtables in power point slides via matlab. so then the problem arises.
Stephen23
Stephen23 2022-10-30
"How can adapt in matlab arrays?"
By more slow, complex, inefficient, obfuscated code using the approach that you used to generate all of those variables. Bad data design forces you into writing bad code.
If you had sensibly used indexing as Askic V showed, then this would be simpler...

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更多回答（1 个）

Askic V
Askic V 2022-10-25
编辑：Askic V 2022-10-25
Ran in:

1 个投票

Ran in:
I'm not really sure how you want to add subtables to power point slides, but you can create subtables in the following way:
T = randi(10, 53,3);
chunkSize = 8; % chunk size from number of rows
noOfChunks = ceil(size(T,1) / chunkSize);
rows = size(T,1);
cellArray = cell(0,3);
subTableNames = {};
for ii = 1:noOfChunks
start_idx = (ii-1)*chunkSize+1;
if ii == noOfChunks
cellArray{ii} = T(start_idx:end, :);
else
cellArray{ii} = T(start_idx:start_idx+chunkSize-1, :);
end
subTableNames{ii} = ['T', num2str(ii)];
end
T2 = cell2table(cellArray(:).', 'VariableNames', subTableNames(:))
T2 = 1×7 table
T1 T2 T3 T4 T5 T6 T7 ____________ ____________ ____________ ____________ ____________ ____________ ____________ {8×3 double} {8×3 double} {8×3 double} {8×3 double} {8×3 double} {8×3 double} {5×3 double}
T2.T1
ans = 1×1 cell array
{8×3 double}
For the purpose of power point slide, I guess the above suggested solution with evail is fine.
However, for other applications, please read this:
https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

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