List of lists manipulation

[woooee]

First, descriptive variable names help you understand what the code is doing. And using i, l, or O as single digit variable names can be confusing as the can look like numbers.

import pprint

def change_list(board):
    for row_num in range(16):
        row=board[row_num]
        for column in range(16):
            if row[column] == 3:
                ## column before
                if column-1 >= 0 and board[row_num][column-1]==0:
                    board[row_num][column-1]=3
                ## column after
                if column+1 < 16 and board[row_num][column+1]==0:
                    board[row_num][column+1]=3
                ## row above
                if row_num-1 >= 0 and board[row_num-1][column]==0:
                    board[row_num-1][column]=3
                ## row below
                if row_num+1 < 16 and board[row_num+1][column]==0:
                    board[row_num+1][column]=3

                ## if you continue on the program will find the column+1 and their neighbors will 
                ## be changed, and then the row+1 will be found, etc. until the end of the list
                return board

board = [[0 for x in range (16)] for y in range(16)]
board[5][2]=3
board=change_list(board)
pprint.pprint(board)