MATLAB: How to find the indices of the value of the matrix

indices matrix

How can I find the indices and exactly position of the value of the attached file. For example find index of value = -69.19 from the attached file.

Thanks

Best Answer

The answer depends entirely on how you define "equals" for floating point numbers:

>> [R,C] = find(abs(XX - -69.19)<1e-4)
R = []
C = []
>> [R,C] = find(abs(XX - -69.19)<1e-3)
R =  25
C =  124
>> [R,C] = find(abs(XX - -69.19)<1e-2)
R =
    3
    6
   10
   14
   17
   18
   21
   25
   29
   32
C =
   108
   110
   113
   116
   118
   119
   121
   124
   127
   129

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A = rand(3);                                    % Create Data
[Amin,idx] = min(A(:));                         % One Option
[r,c] = ind2sub(size(A), idx)
[r,c] = find(A == min(A(:)))                    % Another Option
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For your sample data, this works:

x=[0 1 2 3 4 4 5 6 7 7 8 9 10 11 12 13 14 14 15 16 17 18 19 20];
y=[1 2 5 3 4 8 6 5 8 5 8 6 85 85 66 44 55 66 88 77 99 88 55 66];
xi=[0 5 10 15 20];
dup = find(diff([eps x]) == 0);                                     % Find Duplicated ‘x’ Values
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yi = interp1(x, y, xi, 'linear', 'extrap');                         % Interploate
yi =
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If you have more than one repeated consecutive ‘x’ value, this gets a bit more involved, but the same approach applies.

Best Answer

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