How to identify duplicate elements index values in this array without deleting them
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A=[53 54 80 1
21 43 12 0
27 71 14 0
52 55 70 23
36 69 26 0
46 66 38 0
68 78 60 0
59 3 48 0
74 7 42 0
42 17 74 0
67 30 64 0
64 35 67 0]
how to identify duplicate elements index values in this array without deleting them like 67 is repeated twice and so as 64
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Image Analyst
2021-7-25
Try this:
A = [53 54 80 1
21 43 12 0
27 71 14 0
52 55 70 23
36 69 26 0
46 66 38 0
68 78 60 0
59 3 48 0
74 7 42 0
42 17 74 0
67 30 64 0
64 35 67 0]
minValue = min(A(:))
maxValue = max(A(:))
[counts, edges] = histcounts(A, minValue : maxValue)
for k = 1 : length(counts)
if counts(k) >= 2
fprintf('%f is in there %d times.\n', edges(k), counts(k));
end
end
You'll see:
0.000000 is in there 10 times.
42.000000 is in there 2 times.
64.000000 is in there 2 times.
67.000000 is in there 2 times.
74.000000 is in there 2 times.
3 个评论
sakshi chopra
2021-7-25
Image Analyst
2021-7-26
@sakshi chopra, you didn't mention any of that originally.
To find out the rows that have duplicate values within the row, do this:
[rows, columns] = size(A)
for row = 1 : rows
% Get the whole row.
thisRow = A(row, :);
% Delete anything that has a value of 0
thisRow(thisRow == 0) = [];
% Find the number of unique values
uniqueValues = unique(thisRow);
if length(thisRow) > length(uniqueValues)
fprintf('Row %d has at least one duplicate value.n', row);
end
end
Note that no row has duplicate values in the example you gave.
If you want to find duplicates anywhere in the array, even if the duplicate lives on a different row or column, and ignore zeros, use this:
A = [53 54 80 1
21 43 12 0
27 71 14 0
52 55 70 23
36 69 26 0
46 66 38 0
68 78 60 0
59 3 48 0
74 7 42 0
42 17 74 0
67 30 64 0
64 35 67 0]
minValue = min(A(:))
maxValue = max(A(:))
[counts, edges] = histcounts(A, minValue : maxValue)
ca = cell(1, length(counts));
for k = 1 : length(counts)
if counts(k) >= 2 && edges(k) ~= 0
fprintf('%f is in there %d times at these locations.\n', edges(k), counts(k));
% Find locations where this value lives.
[r, c] = find(A == edges(k));
ca{k} = [r, c];
for k2 = 1 : length(r)
fprintf(' at row %d, column %d.\n', r(k2), c(k2));
end
end
end
You see
42.000000 is in there 2 times at these locations.
at row 10, column 1.
at row 9, column 3.
64.000000 is in there 2 times at these locations.
at row 12, column 1.
at row 11, column 3.
67.000000 is in there 2 times at these locations.
at row 11, column 1.
at row 12, column 3.
74.000000 is in there 2 times at these locations.
at row 9, column 1.
at row 10, column 3.
and ca is a cell array that contains the rows and columns that the number appears in for each number. It's a cell array because each number could appear a different number of times (otherwise you could have used a nromal double 3-D array).
sakshi chopra
2021-7-26
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