If you want to write a sudoku solver, you can start with this code. It loads a game from a string, and can pretty-print the "possible values" of the fields.

sudoku-start.py

# sudoku-starter-kit, lars.rasmusson@gmail.com, 2013-04-30
game = '.8...6...|32.9.47..|.4...7.6.|93..1....|......8.9|8..2.....|...4..17.|.7...89..|..4......'
def rc(r,c): return (r-1)*9+(c-1)
def init_sud(sud):
    v=[]
    for c in sud:
        if c in "123456789": v.append([int(c)])
        elif c in ".": v.append(range(1,10))
    assert(len(v)==81)
    return v
    
def pprint(v):
    for rr in range(27):
        ss=""
        for cc in range(27):
            r,c=rr//3+1,cc//3+1
            i=3*(rr%3)+(cc%3)+1
            ss += str(i) if i in v[rc(r,c)] else '.'
            if (cc+1)%3==0: ss+=' '
            if cc+1 in [9,18] : ss += ' | '
        print(ss)
        if (rr+1)%3==0: print() 
        if rr+1 in [9,18] : print('-'*41+'\n')


v=init_sud(game)
pprint(v)