Python dataframe nearest value

Question

i´ve this panda data frame board look a like:

   0  1  2  3  4  5  6  7  8  9
0  0  0  0 -1  0  0  0  0  0  0
1  0 -1  0  0  0  0  0 -1  0  0
2  0  0  0  0 -1