how to exclude some value from matrix?

sumnot3([1 2 3; 4 5 6; 7 8 9]) % correct answer 1+2+4+5+6+7+8+9=42

function mod_sum = sumnot3(A)
    [rows cols] = size(A);
    Avec = A(:);
    mod_sum = sum(Avec);
    % code to add to mod_sum entries of A not equal to 3
end

how to get the sum all the elements inside matrix A, excluding 3?

[Arif Hoq]

You can try with this:

function mod_sum = sumnot3(A)
    [rows cols] = size(A);    
    A3=A(1,end);
    rep=A3==3;
    A(rep,end)=0;
    mod_sum = sum(A,'all');
    % code to add to mod_sum entries of A not equal to 3
end

Answer 1

[DGM]

It's unclear whether you want to exclude A(1,3) or whether you want to exclude the number 3 regardless of its location.

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

B1 = sum(A(:)) - A(1,3)

B1 = 42

B2 = sum(A(A~=3)) % works for integers

B2 = 42

[Karanpreet Singh]

Thank you