how to change string matrix to a integer matrix

IIUC, you need map and stack

map_dict = {'republican' : 2,
           'democrat' : 3,
           'y' : 1,
           'n' : 0,
           '?' : -1}

df1 = df.stack().map(map_dict).unstack()

print(df1)

   0   1   2   3   4   5   6   7   8   9   10  11  12  13  14  15  16
0   2   0   1   0   1   1   1   0   0   0   1  -1   1   1   1   0   1
1   2   0   1   0   1   1   1   0   0   0   0   0   1   1   1   0  -1
2   3  -1   1   1  -1   1   1   0   0   0   0   1   0   1   1   0   0
3   3   0   1   1   0  -1   1   0   0   0   0   1   0   1   0   0   1