MATLAB: How to formulate logical matrix in a loop

loop

i am having a matrix and want to separate them in the depending on its value

A=[1,2,3,4,5,6,7,8,9,10]

expected result are

idx1=[1,0,0,0,0,0,0,0,0,0]   % for 1
...
idx10=[0,0,0,0,0,0,0,0,0,1] % for 10

A = 1:10;
idx = A(:) == A(:)'

If your values are always sorted, as in your example, then I believe this will compactly do what you want:

indexToDuplicates = [nan(1,size(A,2));diff(A)]==0;
A(indexToDuplicates) = 0;

You don't even have to split that into two lines, but I thought it might be clearer what I am doing. You could do

A([nan(1,size(A,2));diff(A)]==0) = 0;

You can use ismember to generate the logical indices. In the same order as a:

>> idx = ismember(a(:,1:2),b,'rows');
>> a(idx,:)
ans =
    3    7    0
    5   10    0

Or in the same order as b:

>> [~,idx] = ismember(b,a(:,1:2),'rows');
>> a(idx,:)
ans =
    5   10    0
    3    7    0