Combining text with non-zero elements of a 2D array

I have a numerical array that is "almost" diagonal, so it looks like this:

N=[10 0 0 0 0; 0 20 0 0 0; 10 0 20 0 0; 0 0 0 10 0; 0 0 0 0 30]

N = 5×5

10 0 0 0 0 0 20 0 0 0 10 0 20 0 0 0 0 0 10 0 0 0 0 0 30

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I also have a cell array with the same number of rows, which looks like this:

C={'ABC';'DEF';'GHI';'JKL';'MNO'}

C = 5x1 cell array
    {'ABC'}
    {'DEF'}
    {'GHI'}
    {'JKL'}
    {'MNO'}

I would like to create a row array that takes the non-zero values of N, and combines them with the text in C to give an output like this:

CN={'ABC10_GHI10' 'DEF20' 'GHI10' 'JKL10' 'MNO30'}

CN = 1x5 cell array
    {'ABC10_GHI10'}    {'DEF20'}    {'GHI10'}    {'JKL10'}    {'MNO30'}

In other words, it must combine all the non-zero values of each column with text of respective indices.

Answer 1

[Stephen23]

Without an intermediate matrix:

N = [10,0,0,0,0;,0,20,0,0,0;,10,0,20,0,0;,0,0,0,10,0;,0,0,0,0,30]

N = 5×5

10 0 0 0 0 0 20 0 0 0 10 0 20 0 0 0 0 0 10 0 0 0 0 0 30

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C = {'ABC';'DEF';'GHI';'JKL';'MNO'}

C = 5x1 cell array
    {'ABC'}
    {'DEF'}
    {'GHI'}
    {'JKL'}
    {'MNO'}

[X,Y,V] = find(N);
F = @(x)cellstr(join(""+C(X(x))+V(x),'_'));
Z = 1:numel(X);
CN = accumarray(Y,Z(:),[],F)

CN = 5x1 cell array
    {'ABC10_GHI10'}
    {'DEF20'      }
    {'GHI20'      }
    {'JKL10'      }
    {'MNO30'      }

[Saeid]

Thanks Stephen!

Answer 2

[Voss]

Here's one way:

N=[10 0 0 0 0; 0 20 0 0 0; 10 0 20 0 0; 0 0 0 10 0; 0 0 0 0 30]

N = 5×5

10 0 0 0 0 0 20 0 0 0 10 0 20 0 0 0 0 0 10 0 0 0 0 0 30

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C={'ABC';'DEF';'GHI';'JKL';'MNO'}

C = 5x1 cell array
    {'ABC'}
    {'DEF'}
    {'GHI'}
    {'JKL'}
    {'MNO'}

n_col = size(N,2);
tmp = compose('%s%d',string(C),N)

tmp = 5x5 cell array
    {'ABC10'}    {'ABC0' }    {'ABC0' }    {'ABC0' }    {'ABC0' }
    {'DEF0' }    {'DEF20'}    {'DEF0' }    {'DEF0' }    {'DEF0' }
    {'GHI10'}    {'GHI0' }    {'GHI20'}    {'GHI0' }    {'GHI0' }
    {'JKL0' }    {'JKL0' }    {'JKL0' }    {'JKL10'}    {'JKL0' }
    {'MNO0' }    {'MNO0' }    {'MNO0' }    {'MNO0' }    {'MNO30'}

CN = cell(1,n_col);
idx = N ~= 0;
for ii = 1:n_col
    CN{ii} = strjoin(tmp(idx(:,ii),ii),'_');
end

disp(CN)

    {'ABC10_GHI10'}    {'DEF20'}    {'GHI20'}    {'JKL10'}    {'MNO30'}

Answer 3

[Voss]

Here's one way:

N=[10 0 0 0 0; 0 20 0 0 0; 10 0 20 0 0; 0 0 0 10 0; 0 0 0 0 30]

N = 5×5

10 0 0 0 0 0 20 0 0 0 10 0 20 0 0 0 0 0 10 0 0 0 0 0 30

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C={'ABC';'DEF';'GHI';'JKL';'MNO'}

C = 5x1 cell array
    {'ABC'}
    {'DEF'}
    {'GHI'}
    {'JKL'}
    {'MNO'}

n_col = size(N,2);
tmp = compose("%s%d",string(C),N)

tmp = 5x5 string array
    "ABC10"    "ABC0"     "ABC0"     "ABC0"     "ABC0" 
    "DEF0"     "DEF20"    "DEF0"     "DEF0"     "DEF0" 
    "GHI10"    "GHI0"     "GHI20"    "GHI0"     "GHI0" 
    "JKL0"     "JKL0"     "JKL0"     "JKL10"    "JKL0" 
    "MNO0"     "MNO0"     "MNO0"     "MNO0"     "MNO30"

CN = strings(1,n_col);
idx = N ~= 0;
for ii = 1:n_col
    CN(ii) = join(tmp(idx(:,ii),ii),'_');
end

disp(CN)

    "ABC10_GHI10"    "DEF20"    "GHI20"    "JKL10"    "MNO30"

CN = cellstr(CN)

CN = 1x5 cell array
    {'ABC10_GHI10'}    {'DEF20'}    {'GHI20'}    {'JKL10'}    {'MNO30'}