MATLAB: Make a better code to check the neighbours of a cell in a matrix and replace a value

matrix

Hello, I want to ask for help to make my code better, or maybe simpler. My idea is to check the 8 neighbors of my cell isla(i,j)==2 and if one of them has the value 0, insert in that location the value 2, but only in the first one that the code finds.
My code is:
for i=3:len+2
    for j=3:len+2
        if isla(i,j)==2 
            if isla(i,j+1)==0 %espacio a la derecha vacio
                isla(i,j+1)=2;
            elseif isla(i,j-1)==0 %espacio a la izquierda vacio
                 isla(i,j-1)=2;
            elseif isla(i+1,j)==0 %espacio de abajo vacio
                 isla(i+1,j)=2;
            elseif isla(i-1,j)==0 %espacio de arriba vacio
                 isla(i-1,j)=2;
            elseif isla(i-1,j-1)==0
                isla(i-1,j-1)=2;
            elseif isla(i-1,j+1)==0
                isla(i-1,j+1)=2;
            elseif isla(i+1,j+1)==0
                isla(i+1,j+1)=2;
            elseif isla(i+1,j-1)==0
                isla(i+1,j-1)=2;
            end
end 
end
end
end
Hope you can see the problem is that the code isn't simple. I wish I could use fewer lines to don't have to modify the entire code every time when I have to change the conditions. I hope someone can help me. I apologize if I misspelled a word, English isn't my native language. Greetings

Best Answer

Do you have the Image Processing Toolbox? And are all the numbers guaranteed to be 0 or positive?
If you want any neighbor of a 2 that is a 0 to be set to 2, then don't use elseif - have separate if statements.
if isla(i,j+1)==0 %espacio a la derecha vacio
                isla(i,j+1)=2;
end
if isla(i,j-1)==0 %espacio a la izquierda vacio
                 isla(i,j-1)=2;
end
if isla(i+1,j)==0 %espacio de abajo vacio
                 isla(i+1,j)=2;
end
if isla(i-1,j)==0 %espacio de arriba vacio
                 isla(i-1,j)=2;
end
if isla(i-1,j-1)==0
                isla(i-1,j-1)=2;
end
if isla(i-1,j+1)==0
                isla(i-1,j+1)=2;
end
if isla(i+1,j+1)==0
                isla(i+1,j+1)=2;
end
if isla(i+1,j-1)==0
                isla(i+1,j-1)=2;
end
Related Question