I'm trying to extract from a 2-D matrix with id values the neighboring ids of each element on the board.

I have a list of of IDs and their coordinates (of n elements), and I'm creating the following:
(Example for left neighbor only).

```
%Left:
leftIndex = (currentLocationIndex - bSize);
hasLeft = leftIndex >= 1; %If element on first col, value will be 0 or negative
hasLeft = hasLeft(:) & board(leftIndex)==0;

```

I get:
Subscript indices must either be real positive integers or logicals.

I want to use the pricipal of && operand or some other logic.
the leftIndex contains all the indices left to a current index in the table.
Some are legal some arn't. If hasLeft vector is true then the leftIndex vector value is legal in the 'board'.

How can I check for a neighbor in a certain value of the vector only if the hasLeft is true?

Thanks!