# Don't understand logic of the index locating

#1

The code behaves correctly but i don't understand the concept .

what is the logic behind ::

example :: print board[2][3]
&
board[guess_row][guess_col]="X"

How is it able to multiply the indexes to print ::

only one single "O" from row 3 and column 4.
Instead of two "O"'s for the two indexes.

magic?

``````from random import randint

board = []

for x in range(0, 5):
board.append(["O"] * 5)

def print_board(board):
for row in board:
print " ".join(row)

print_board(board)

def random_row(board):
return randint(0, len(board) - 1)

def random_col(board):
return randint(0, len(board[0]) - 1)

ship_row = random_row(board)
ship_col = random_col(board)
guess_row = int(raw_input("Guess Row:"))
guess_col = int(raw_input("Guess Col:"))

print ship_row
print ship_col

if guess_row == ship_row and guess_col == ship_col:
print"Congratulations! You sank my battleship!"
else:
print"You missed my battleship!"

**_`board[guess_row][guess_col]="X"`_**

print print_board(board)``````

#2

`board[2]` is a list
If you have a list, you can get the fourth element by adding `[3]` after it

`board[2][3]`

#3

nvm thank you. i understand now.