I have a line of code in matlab for which i am selecting a subset of a matrix:

`A(3:5,1:3);`

Now i want to adapt this line, to only select rows for which all three values are larger than zero:

`(A(3:5,1:3) > 0);`

But apparently i am not doing this right. How do i select part of the matrix, and also make sure that only the rows (for which all three values are) larger than zero are selected? 

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EDIT: To clarify: lets say that i have a matrix of coordinates called A, that looks like this:

```
Matrix A [5,3]

3  4  0
0  1  0
0  3  1
0  0  0
4  8  7

```

Now i want to select only part [3:5,1:3], and of that part i only want to select row 3 and 5. How do i do that?