[...]在python中作为输出意味着什么？

Question

我正在尝试在战舰板上装船.下面代码中的函数应该使用许多船只和一个板(数组数组)作为参数.当我在终端运行时,我得到:

[[1, [...]], [1, [...]], [2, [...]]]

这是什么意思？如何在此输出中用0到2的随机整数替换[...]？

from random import randint

def print_board(board):
    for row in board:
        print " ".join(row)
def random_row(board):
    return randint(0, len(board) - 1)
def random_col(board):
    return randint(0, len(board[0]) - 1)

def set_the_ships(num_ships,board):
    ship_list = []
    for i in range(num_ships):
        ship_row = random_row(board)
        ship_col = random_col(board)    
        position = [ship_row,ship_list]
        for j in range(i - 1):
            while (position[0] == ship_list[j][0] and position[1] == ship_list[j][1]):
                ship_row = random_row(board)
                ship_col = random_col(board)    
                position = [ship_row,ship_list]
        ship_list.append(position)
    return ship_list

print set_the_ships(3,[[0,0,0],[0,0,0],[0,0,0]])

Answer 1

...意味着存在引用循环。

>>> l = []
>>> l.append(l)
>>> l
[[...]]