MATLAB: Find similar element in a matrix

element of a matrix

I have several questions. First, I have several vectors with different dimensions. I want to put them all in one matrix. I would fill it with zero to make them the same size as follows.
Do you know how to do it?
X= [1 2 3 9 20 67 81 43 101 24;
43 42 88 20 43 67 101 0 0 0;
22 44 0 0 0 0 0 0 0 0;
10 20 67 43 101 0 0 0 0 0;
]
I have a matrix, I want to generate a vector of all elements that are similar in all raws of that matrix. Some raws might have nothing similar as other raws. I count those element similar as if they are similar (e.g. 22 is similar to 22) or they are + – 2 different (e.g. 22 is similar to 24 or 20) the dimension of each raw is different. for example The similarity should be at least between three raws that we select that element.
Then I want to get a vector of all similar elements in all raws as follows
Y=[20 43 67];

Best Answer

First question: create
   X = zeros(10,4);
then plug in you vectors, e.g.,
     X(1,1:numel(v1)) = v1;
Second point (I'm sure it can be written in a more compact way but it works):
X= [1 2 3 9 20 67 81 43 101 24;...
43 42 88 20 43 67 101 0 0 0;...
22 44 0 0 0 0 0 0 0 0;...
10 20 67 43 101 0 0 0 0 0;...
] ;
n = unique(X(1,:));
X(X==0)=NaN; % So you don't consider the zeros
nrow = size(X,1)-1;
Y = zeros(numel(X),1);cont = 0;
for i = 1:numel(n)    
    x = X(2:end,:);
   [row,~] = find(x >= n(i)-2 & x <= n(i)+2);
   if(numel(unique(row)) == nrow)
       cont = cont + 1;
       Y(cont) = n(i);
   end
end
Y = Y(1:cont)
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