how to delete diagonal values in a matrix?

Hi everyone;
For example I got an matrix that all diagonal values are zero and I want to remove them.
A=[0 5 4 3
3 0 5 1
4 2 0 2
3 8 6 0]
I want to get a new matrix like that:
Anew=[ 5 4 3
3 5 1
4 2 2
3 8 6]
Is there any suggestion?
Regards...

3 commentaires

v=find(A==0) A(v)=[]
Notwithstanding the fact that this will flatten A which is not what the OP is looking for, the find is completely unnecessary here.
A(A == 0) = [];
will produce the same result.
bilgesu ak
bilgesu ak le 18 Jan 2016
I tried it but it gives a row vector that is:
[3 4 3 5 2 8 4 5 6 3 1 2]
I need a matrix that only diagonal values are gone but all rest is same...

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 Réponse acceptée

Guillaume
Guillaume le 18 Jan 2016
One possible way:
Anew = reshape(nonzeros(A'), size(A, 2)-1, [])'

5 commentaires

Thorsten
Thorsten le 18 Jan 2016
That's neat.
bilgesu ak
bilgesu ak le 18 Jan 2016
Thanks Guillaume;
At last it works true.
Regards...
Guillaume
Guillaume le 18 Jan 2016
Modifié(e) : Guillaume le 18 Jan 2016
Note that it assumes that the only zeros are on the diagonal. A safer solution would be:
Atemp = A';
Anew = reshape(Atemp(~eye(size(Atemp))), size(A, 2)-1, [])'
Stephen23
Stephen23 le 18 Jan 2016
+1 very nice solution (given zeros only on the diagonal...)
bilgesu ak
bilgesu ak le 21 Jan 2016
thank you Guillaume, this solution only focuses on diagonals...

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Plus de réponses (1)

shubhashree bal
shubhashree bal le 14 Oct 2021

0 votes

Try this:
A=[0 5 4 3
3 0 5 1
4 2 0 2
3 8 6 0];
u=1;
value =size(A,1)+1;
row_value_end=size(A,1)-1;
col_value_end=size(A,1);
for k=1:size(A,1)
u(k+1)=u(k)+value;
end
g= A.';
g(u(1:end-1))=[];
y= reshape(g,[row_value_end,col_value_end]);
b=y.';

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