Finding equal members in a vector

23 visualizaciones (últimos 30 días)
mr mo
mr mo el 17 de Dic. de 2017
Comentada: Star Strider el 17 de Dic. de 2017
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.
  1 comentario
Image Analyst
Image Analyst el 17 de Dic. de 2017
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.

Iniciar sesión para comentar.

Respuestas (4)

jean claude
jean claude el 17 de Dic. de 2017
find(x==10)
  2 comentarios
mr mo
mr mo el 17 de Dic. de 2017
Assume that I don't know the values of the vector.
jean claude
jean claude el 17 de Dic. de 2017
Editada: jean claude el 17 de Dic. de 2017
[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

Iniciar sesión para comentar.


YT
YT el 17 de Dic. de 2017
Editada: YT el 17 de Dic. de 2017
Found your answer in this post
  2 comentarios
mr mo
mr mo el 17 de Dic. de 2017
In my question I want to have the below form of output
1 3 5
2 8
that indicates
V(1) = V(3) = V(5)
and
V(2) = V(8)
YT
YT el 17 de Dic. de 2017
Something like this then?
clear C
V = [ 10 13 10 20 10 95 70 13];
unqV = unique(V);
for i = 1:length(unqV);
C{i,1} = unqV(i)
C{i,2} = find(V==unqV(i));
end
%C = {10,[1 3 5];
% 13,[2 8];
% 20,4;
% 70,7;
% 95,6}

Iniciar sesión para comentar.


Star Strider
Star Strider el 17 de Dic. de 2017
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’.
  4 comentarios
mr mo
mr mo el 17 de Dic. de 2017
Is there any possibility to use other command except bsxfun and accumarray ?
Star Strider
Star Strider el 17 de Dic. de 2017
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.

Iniciar sesión para comentar.


Jos (10584)
Jos (10584) el 17 de Dic. de 2017
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)

Categorías

Más información sobre Line Plots en Help Center y File Exchange.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by