Select rows in a given table according to 3 criteria

Question

NA 2021-6-5

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/848300-select-rows-in-a-given-table-according-to-3-criteria

评论： NA 2021-6-5

I have a table data like this

%% Data of Table
Name = {'A';'A';'A';'B';'B';'C';'D'}; 
index = [1;9;14;16;19;38;55]; 
Var_1 = [1;0;0;0;0;1;1];   
Var_2 = [0;1;0;1;0;0;1]; 
Var_3 = [0;0;1;0;0;0;0]; 
Var_4 = [0;0;1;1;1;0;0]; 
Var_5 = [1;1;0;1;0;0;0]; 
Var_6 = [1;1;1;0;0;1;1]; 
 
T = table(Name,index,Var_1,Var_2,Var_3,Var_4,Var_5,Var_6);
V = {[1,2],[2,6],[1,3,4],[4,8,9],[1,9,32,40],[1,2,3,45,53]};
F = @(n)sprintf("{%s}",join(string(n),","));
T.Properties.VariableNames(3:8) = cellfun(F,V);

I have two groups in the above table

group_1 = [3;4;5];
group_2 = [6;7;8];
T_group_1= T(:,group_1);
T_group_2= T(:,group_2);

I want to choose three rows of the table according to this criteria

1) The rows should be belong to 'A' and 'B'.
2) Sum of the any column of chosen row should be smaller or equal 2 for T_group_1
3) Sum of the any column of chosen row should be greater than 3 for T_group_2

I have came up with the following code

%% first criteria
T_new = T((strcmp(T.Name, 'A') | strcmp(T.Name, 'B')),:);
group_1_new = [3;4;5]-2;
group_2_new = [6;7;8]-2;
%% choose row index
chosen_index_candidate = cell([],1);
i = 1;
m = 0;
while 1
    chosen_index = randperm(size(T_new{:,3:end},1),3);
    sum_of_each_col = sum(T_new{chosen_index,3:end},1);
    m = m+1;
    if m==40   % I want to find some number to break the loop 
        break
    end
    if any(sum_of_each_col(:,group_1_new)<=2) && any(sum_of_each_col(:,group_2_new)>=3) %% second and third criteria
        if i==1
            chosen_index_candidate{i} = chosen_index;
            i = i+1;
        else
            if    any(cell2mat(cellfun(@(x)all(ismember(sort(x),sort(chosen_index))),chosen_index_candidate,'uni',0)))==0
                chosen_index_candidate{i} = chosen_index;
                i = i+1;   
            end   
        end   
    end  
end

I think the code is not written in proper way especially break from while loop

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Answer 1

J. Alex Lee 2021-6-5

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/848300-select-rows-in-a-given-table-according-to-3-criteria#answer_717305

This is small enough you could generate the full list of combinations

% generate all combinations
alltriplets = nchoosek(1:7,3)
% randomize
iterlist = randperm(size(alltriplets,1))
% replace your while loop with a for loop over all possible triplets
for i = iterlist
end

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J. Alex Lee 2021-6-5

I guess that should work, but I personally don't like the counter approach. You can create a true/false mask that can be applied to your randomly permuted list of triplets

alltriplets = nchoosek(1:size(T_new,1),3); % generate all combinations
iterlist = randperm(size(alltriplets,1)); % randomize
meetsCriteria = false(size(alltriplets,1),1);
for i = iterlist
    chosen_index = alltriplets(i,:);
    sum_of_each_col = sum(T_new{chosen_index,3:end},1);
    if any(sum_of_each_col(:,group_1_new)<=2) && any(sum_of_each_col(:,group_2_new)>=3)
        meetsCriteria(i) = true;
    end
end
% then you can extract the rows of alltriplets that satisfies your
% condition as an array, rather than a cell
chosen_index_candidate = alltriplets(meetsCriteria,:)