Check if a certain value is in the vector

Question

I created the vector fragil that will accept various inputs from the user, inputs that will (or will not) be the position of other elements in another matrix. I used the following function to create the vector fragil:

fragil = zeros(1, numIdosos);

And then I wanted to check on the second if of the excerpt below if the j belongs to the vector fragil. I mean, is there any way to verify that the j belongs to the vector fragil without adding the for extra that travels the vector fragil whole?

for j=1:numIdosos
     if MCobertura(iMax,j)==1
             contador(j)=contador(j)+1;
     end
     if contador (j)>1 
         porCobrir(j)=0;
     end
 end
 n_porCobrir=sum(porCobrir);
end
end

Answer 1

You can use the find to return the index if the number you are looking for exists inside the vector:

x = [1     3     5     7     9    11    13    15    17    19]

k = find(x==3);

if isempty(k)

    disp('nao achei')

else

    disp('achei')

end

In the above example I am using the find to find the occurrence of the number 3 within the vector x, if found it will place the index inside the variable k, after that I compare with the if if there was a return or not, if the variable k empty there is no occurrence of the number you are looking for in the vector.