Finding equal members in a vector
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Hi. My question is how can I find equal members in a vector with their indices.
For example I have this vector.
V = [ 10 13 10 20 10 95 70 13];
Thanks a lot.
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Image Analyst
2017년 12월 17일
This has nothing to do with the MATLAB compiler product or the Coder product, or a GUI or 3-D plots, or nearly all the tags you applied. Save yourself some time and only put the relevant tags that will help people.
답변 (4개)
jean claude
2017년 12월 17일
find(x==10)
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jean claude
2017년 12월 17일
편집: jean claude
2017년 12월 17일
[a] = histc(x,unique(x));
t=unique(x);
c=find(a>1);
d=0;
for i=1:length(c);
d=[d find(x==t(c(i)))];
end
d(1)=[]; % d is the output
Star Strider
2017년 12월 17일
If you only want the repeated values in the vector and their indices:
V = [ 10 13 10 20 10 95 70 13]; % Original Vector
[Vu,~,I] = unique(V(:), 'stable'); % Unique Values
Tally = accumarray(I, 1); % Count Occurrences
Idx = bsxfun(@eq, V, Vu(Tally > 1)) .* (1:length(V)); % Determine Indices Of Multiple Values Only
OutD = [Vu(Tally > 1) Idx] % Double Matrix Result
for k1 = 1:size(Idx,1)
IdxC{k1} = Idx(k1,(Idx(k1,:)>0)); % Keep Only Non-Zero Values
OutC{k1} = {OutD(k1,1) IdxC{k1}}; % Cell Array Result
end
celldisp(OutC) % View Cell Array (Optional)
OutD =
10 1 0 3 0 5 0 0 0
13 0 2 0 0 0 0 0 8
The ‘OutC’ cell array result eliminates the zeros in the ‘(2:end)’ columns of ‘OutD’.
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Star Strider
2017년 12월 17일
Not that I am aware of. It is necessary to accumarray (or one of the histogram functions) to count the occurrences. Using bsxfun is necessary to do the array calculations.
Jos (10584)
2017년 12월 17일
V = [ 10 13 10 20 10 95 70 13];
[VU, ~, j] = unique(V)
P = accumarray(j, 1:numel(V), [] ,@(x) {x})
% P{k} holds all the indices where V equals VU(k)
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