# Selecting numbers in matrix that are repeated

2 visualizaciones (últimos 30 días)
Cside el 1 de Dic. de 2019
Comentada: Star Strider el 1 de Dic. de 2019
I have a 60x5 matrix A and would like to find the answer vector that lists all the numbers in A that appeared at least 2 times/remove those numbers that only appeared once. How may I write for this?
(A contains some NaNs too)
Thank you! :)
##### 0 comentariosMostrar -1 comentarios más antiguosOcultar -1 comentarios más antiguos

Iniciar sesión para comentar.

Star Strider el 1 de Dic. de 2019
Try this:
A = randi(1000, 60, 5); % Create Matrix
[Au,~,ix] = unique(A,'stable'); % Unique elements in ‘A’
tally = accumarray(ix,1); % Number Of Occurrences Of Each
keep = tally > 1; % Keep Indices Of Occurrences > 1
out1 = [Au(keep), tally(keep)]; % Display Numbers & Occurrences
Ai = ismember(A,out1(:,1)); % Return Logical Index Of Occurrences > 1
Anew = A .* Ai; % Matrix With ‘Single-Occurrence’ Elements Eliminated
The ‘Anew’ matrix has 0 values for the elements that are not repeated, those that are repeated appear in their expected locations.
If you only want the values of the numbers that aare repeated, and the number of repeats, those are contained in the ‘out1’ matrix.
##### 2 comentariosMostrar 1 comentario más antiguoOcultar 1 comentario más antiguo
Star Strider el 1 de Dic. de 2019
As always, my pleasure!

Iniciar sesión para comentar.

### Más respuestas (1)

KALYAN ACHARJYA el 1 de Dic. de 2019
[N,edges]=histcounts(A,unique(A))
result_array=edges(N>1)
##### 1 comentarioMostrar NingunoOcultar Ninguno
Cside el 1 de Dic. de 2019
there seems to be an error using histcounts (needs to be monotonically increasingly) - had a similar code with you too :) thank you nonetheless kalyan!

Iniciar sesión para comentar.

### Categorías

Más información sobre Matrix Indexing 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