What does

**print board[2][3]**

mean. What does [2] and [3] mean respectively.

So for

board[2][3]

it refers to index 2 of board and index 3 of board. I thought it was the row number and column number of the board in

**Battleship!****Danger, Will Robinson!!**

You can imagine it as a 2D matrix (in this case; N square brackets N dimensional matrix). First square brackets are rows in the matrix, second brackets are columns.

If it is the row number and column number, why does

board[2][3]

refer to the 3rd row and 4th column.

no, you have a multi dimensional array:

`board = [[1,2,3],[4,5,6][7,8,9]]`

so board[1][1] would be 5, counting starts from zero, so 1 is array 4,5,6, then the second one is the second item in that array (5)

Because counting starts from zero

Oh, thank you. It's indexing the outer list and indexing a inner list to get a certain item within the two lists. Now it makes sense. Thank you. Also, what is a **multi dimensional array**?

arrays are called list in pythons, can be confusing working multiply languages. In that case they are nested lists (list nested inside a list)