def chiffre_barre_ligne(s, r, i):
    """
    Look into every number in line *i*,
    if the number in column *k* ``s[i][k]`` is not null,

    @param      s       current state of the sudoku
    @param      r       array ``r[n] == 0`` means number *n+1* is already taken on this line
    @param      i       line index (0 based)
    """
    for k in range(0, 9):
        if s[i][k] > 0:
            r[s[i][k] - 1] = 0
