My question is similar(the expanded version) to this post:Numpy extract row, column and value from a matrix. In that post, I extract elements which are bigger than zero from the input matrix, now I want to extract **elements on the diagonal**, too. So in this case,

```
from numpy import *
import numpy as np
m=np.array([[0,2,4],[4,0,0],[5,4,0]])
dist=[]
index_row=[]
index_col=[]
indices=np.where(matrix>0)
index_col, index_row = indices
dist=matrix[indices]
return index_row, index_col, dist
```

we could get,

```
index_row = [1 2 0 0 1]
index_col = [0 0 1 2 2]
dist = [2 4 4 5 4]
```

and now this is what I want,

```
index_row = [0 1 2 0 1 0 1 2]
index_col = [0 0 0 1 1 2 2 2]
dist = [0 2 4 4 0 5 4 0]
```

I tried to edit line 8 in the original code to this,

```
indices=np.where(matrix>0 & matrix.diagonal)
```

but got this error,

How to get the result I want? Please give me some suggestions, thanks!