generate out put names and output number dynamically

Question

Amila 2023-2-9

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1909370-generate-out-put-names-and-output-number-dynamically

编辑： Stephen23 2023-2-9

采纳的回答： Stephen23

Im have hard code K but I want to change it so K will be generated i have done that part

the problem is G1 to G5 veriables should be change from G1 to GK

how can I do this

K=5 % specify and hard code K number of clastors

X;

[IDX, centr] = kmeans( X , K , 'distance' , 'sqEuclidean');% K number of clustors

% separate the data into five groups

G1 = Y2(IDX == 1 , : );

G2 = Y2(IDX == 2 , : );

G3 = Y2(IDX == 3 , : );

G4 = Y2(IDX == 4 , : );

G5 = Y2(IDX == 5 , : );

I try this simply didt work

[IDX, centr] = kmeans( X , K , 'distance' , 'sqEuclidean');% K number of clustors

for g=1:K

G(g) = Y2(IDX == g , : )

end

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Stephen23 2023-2-9

编辑：Stephen23 2023-2-9

"the problem is G1 to G5 veriables should be change from G1 to GK"

The problem is that you are forcing meta-data (i.e. pseudo-indices) into variable names.

"how can I do this "

Rather than attempting to force pseudo-indices into variable names, you should be using actual indices.

How to use arrays, loops, and indexing is explained in the introductory tutorials:

https://www.mathworks.com/help/matlab/getting-started-with-matlab.html

The name "MATLAB" comes from "MATrix LABoratory", not from "lets split up the data into lots and lots of separate variables and make working with the data slow and complex". MATLAB is designed to work with arrays. You should use arrays.

Dyuman Joshi 2023-2-9

@Stephen23 I think OP is trying to use arrays but failed in the attempt as they have mentioned.

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Answer 1

Stephen23 2023-2-9

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1909370-generate-out-put-names-and-output-number-dynamically#answer_1167450

编辑：Stephen23 2023-2-9

在 MATLAB Online 中打开

Because you did not upload any data I will use an inbuilt dataset:

S = load('fisheriris.mat');
X = S.meas(:,3:4);

Now lets group that data:

[idx,C] = kmeans(X,2) % keep it simple
idx = 150×1
     2
     2
     2
     2
     2
     2
     2
     2
     2
     2
C = 2×2
    4.9253    1.6818
    1.4922    0.2627
F = @(n) X(idx==n,:);
C = arrayfun(F,1:max(idx),'uni',0)
C = 1×2 cell array
    {99×2 double}    {51×2 double}

Checking:

C{:}
ans = 99×2
7000    1.4000
5000    1.5000
9000    1.5000
0000    1.3000
6000    1.5000
5000    1.3000
7000    1.6000
3000    1.0000
6000    1.3000
9000    1.4000
ans = 51×2
4000    0.2000
4000    0.2000
3000    0.2000
5000    0.2000
4000    0.2000
7000    0.4000
4000    0.3000
5000    0.2000
4000    0.2000
5000    0.1000

Note that splitting up data is often not a good approach, it is the kind of thing that users do because they think it is required for processing of their data. In fact, MATLAB has tools that support working on entire datsets without splitting them up into separate arrays:

https://www.mathworks.com/help/matlab/matlab_prog/split-data-into-groups-and-calculate-statistics.html

https://www.mathworks.com/help/matlab/ref/splitapply.html#bux1l61

https://www.mathworks.com/help/matlab/matlab_prog/grouping-variables-for-splitting-data.html