how to find connected neighbors?

How do I find a neighbor of pixels with a neighbor whose value is 1?

(Loop to find connected neighbors)

I tried to run the operation on this code but failed

[y,x] = find(I) ;
figure
imshow(I)
hold on
plot(x,y,'.b')

i=x(100)
j=y(100)

neighbors(1) = I(i-1,j-1);
plot(i-1,j-1,'*r')
neighbors(2) = I(i-1,j);
plot(i-1,j,'*r')
neighbors(3) = I(i-1,j+1);
plot(i-1,j+1,'*r')
neighbors(4) = I(i,j-1);
plot(i,j-1,'*r')
neighbors(5) = I(i,j+1);
plot(i,j+1,'*r')
neighbors(6) = I(i+1,j-1);
plot(i+1,j-1,'*r')
neighbors(7) = I(i,j);
plot(i,j,'*r')
neighbors(8) = I(i+1,j);
plot(i+1,j,'*r')
neighbors(9) = I(i+1,j+1);
plot(i+1,j+1,'*r')

Answer 1

[KSSV]

If you know the location of the pixel..uou can use knnsearch or rangeseach. YOu can also search in mathworks, this question has been addressed multiple times.