What's the best way to shorten this?

Question

Hans123 2019-5-9

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/461215-what-s-the-best-way-to-shorten-this

评论： Adam Danz 2019-5-13

This is a very lengthy code for something repetitive, I want to know whether there is a simpler, more efficient way of doing this.

The purpose of the code is to load text files and trim them according to the same criteria and check which one is the shortest and use the shortest length in calculations that happen later in the code.

T1 = dlmread("Trial 1");
T2 = dlmread("Trial 2");
T3 = dlmread("Trial 3");
T4 = dlmread("Trial 4");
T5 = dlmread("Trial 5");
T6 = dlmread("Trial 6");
T7 = dlmread("Trial 7");
T8 = dlmread("Trial 8");
T9 = dlmread("Trial 9");
T10 = dlmread("Trial 10");
%removal of unwanted elements from the raw data array
T1(T1(:,11)<=0 ,:) = [];
T1(T1(:,3)==25 ,:) = [];
T1(T1(:,3)<500 ,:) = [];
T1(T1(:,5)==0    ,:)= [];
T1(find(T1(:,12)>780,1):end, :) = [];
T2(T2(:,11)<=0 ,:) = [];
T2(T2(:,3)==25 ,:) = [];
T2(T2(:,3)<500 ,:) = [];
T2(T2(:,5)==0    ,:)= [];
T2(find(T2(:,12)>780,1):end, :) = [];
T2(T2(:,11)<=0 ,:) = [];
T3(T3(:,3)==25 ,:) = [];
T3(T3(:,3)<500 ,:) = [];
T3(T3(:,5)==0    ,:)= [];
T3(find(T3(:,12)>780,1):end, :) = [];
T4(T4(:,11)<=0 ,:) = [];
T4(T4(:,3)==25 ,:) = [];
T4(T4(:,3)<500 ,:) = [];
T4(T4(:,5)==0    ,:)= [];
T4(find(T4(:,12)>780,1):end, :) = [];
T5(T5(:,11)<=0 ,:) = [];
T5(T5(:,3)==25 ,:) = [];
T5(T5(:,3)<500 ,:) = [];
T5(T5(:,5)==0    ,:)= [];
T5(find(T5(:,12)>780,1):end, :) = [];
T6(T6(:,11)<=0 ,:) = [];
T6(T6(:,3)==25 ,:) = [];
T6(T6(:,3)<500 ,:) = [];
T6(T6(:,5)==0    ,:)= [];
T6(find(T6(:,12)>780,1):end, :) = [];
T7(T7(:,11)<=0 ,:) = [];
T7(T7(:,3)==25 ,:) = [];
T7(T7(:,3)<500 ,:) = [];
T7(T7(:,5)==0    ,:)= [];
T7(find(T5(:,12)>780,1):end, :) = [];
T8(T8(:,11)<=0 ,:) = [];
T8(T8(:,3)==25 ,:) = [];
T8(T8(:,3)<500 ,:) = [];
T8(T8(:,5)==0    ,:)= [];
T8(find(T8(:,12)>780,1):end, :) = [];
T9(T9(:,11)<=0 ,:) = [];
T9(T9(:,3)==25 ,:) = [];
T9(T9(:,3)<500 ,:) = [];
T9(T9(:,5)==0    ,:)= [];
T9(find(T9(:,12)>780,1):end, :) = [];
T10(T10(:,11)<=0 ,:) = [];
T10(T10(:,3)==25 ,:) = [];
T10(T10(:,3)<500 ,:) = [];
T10(T10(:,5)==0    ,:)= [];
T10(find(T10(:,12)>780,1):end, :) = [];
L1=length(T1);
L2=length(T2);
L3=length(T3);
L4=length(T4);
L5=length(T5);
L6=length(T6);
L7=length(T7);
L8=length(T8);
L9=length(T9);
L10=length(T10);
Lmin = min([L1(:);L2(:);L3(:);L4(:);L5(:);L6(:);L7(:);L8(:);L9(:);L10(:)]);

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Stephen23 2019-5-13

Using numbered variables is a sign that you are doing something wrong.

Copy-and-pasting code is a sign that you are doing something wrong.

Remember that computers are only really good at one thing: repeatedly doing simple tasks. So when you find yourself copy-and-pasting the same code over and over again, then you are just doing the computer's job for it. Instead get the computer to do it for you: use a loop.

Hans123 2019-5-13

thank you for your inputs, I really appreciate it!

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Answer 1

Adam Danz 2019-5-9

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/461215-what-s-the-best-way-to-shorten-this#answer_374336

编辑：Adam Danz 2019-5-13

在 MATLAB Online 中打开

This should get you started but it's not tested and there will likely be some kinks to work out. I'd be glad to help more if needed.

trials = ["Trial 1", "Trial 2", "Trial 3", "Trial 4", "Trial 5", ...
    "Trial 6", "Trial 7",  "Trial 8",  "Trial 9",  "Trial 10" ];
nTrials = numel(trials);
T = cell(size(trials));
for i = 1:nTrials
    T{i} = dlmread(trials(i));
    %removal of unwanted elements from the raw data array
    T{i}(T{i}(:,11)<=0 ,:) = [];
    T{i}(T{i}(:,3)<500 ,:) = [];
    T{i}(T{i}(:,5)==0    ,:)= [];
    T{i}(find(T{i}(:,12)>780,1):end, :) = [];
end
L = cellfun(@length, T,'UniformOutput', false);
Lmin = min([L{:}]);

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Hans123 2019-5-13

在 MATLAB Online 中打开

this works perfectly, I really appreciate the help. I am relatively new to MATLAB and cell functions as well. I didn't quite understand how this line works

L = cellfun(@length, T,'UniformOutput', false);

Any help would be appreciated.

Cheers

Adam Danz 2019-5-13

在 MATLAB Online 中打开

The first input to cellfun() is a function handle. The second input is a cell array. The cellfun() function applies the function in input #1 to each element of the cell array in input #2. For example, the cell array T (defined below) has 4 elements. The length of the four elements are [3, 4, 5, 2].

T = { [1 2 3], [1 2 3 4], [1 2 3 4 5], [1 2] };

The 'UniformOutput' flag specifies that the output should be stored in a cell array.

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