reinforcement_tic_tac_toe_snippet_5.py

reinforcement_tic_tac_toe_snippet_5.py

def have_same_val(self, axis, item, item_x, item_y):
    """
    Oh boy! without the documentation this would be just 12-14 lines of code.

    Checks if a row(if axis = 0) of the board matrix has same values throughout.
                                or
    Checks if a column(if axis = 1) of the board matrix has same values throughout.

    This is useful to check if a row or column is filled up by the symbol which was added the latest.

    params:

    - axis int: The direction along which operations are to be performed. Can have a value of 0 or 1 only.
        - 0 means row
        - 1 means column
    - item_x int: The row of the matrix in which item has been inserted.
    - item_y int: The column of the matrix in which the item has been inserted.
    - item int: The latest integer inserted into the matrix at row-index = item_x, and column-index = item_y. 
    """
    max_limit, _ = self.board.shape
    # Get the number of rows in the board.

    result = True
    # Optimistic approach, assume the result to be true, 
    # unless proven wrong in the further steps.

    row_idx = col_idx = 0
    # set row_idx and col_idx iteration variables as 0
    # they don't get used much, they are present for code readability.

    main_idx, fixed_idx, ignore_idx = (col_idx, item_x, item_y) \
                                        if axis == 0 \
                                        else (row_idx, item_y, item_x)
    # main_idx: Update this index each iteration of the loop.
    # fixed_idx: Don't modify this index ever.
    # ignore_idx: this is the index of the inserted element 
    #              which doesn't need to be evaluated, so ignore.
    # The if-else ensures weather to increment the row index 
    # or the column index according to the value of the axis.

    while main_idx < max_limit:
        # If the main_idx which starts at 0 is less than number of rows/cols in matrix.
        if main_idx != ignore_idx:
            # And main_idx is not equal to the index of the latest item inserted (ignore_idx)
            # because for a fixed_index if we compare main_idx and ignore_idx it would give us the 
            # latest element added, which will be equal to itself.
            # Learning algorithms are costly, ain't nobady got time fo that!

            board_item = self.board[fixed_idx][main_idx] \
                if axis == 0 \
                else self.board[main_idx][fixed_idx]
            # find the item(board_item) in the matrix 
            # corresponding to main_idx and the fixed_index.
            # It should be an element in the same row or column depending on the axis.

            if board_item != item or board_item == 0:
                # If the board_item found is not equal to the latest item added
                # or if the board item is 0, which is still not marked by bot or player,
                # result is false as the function didn't find all 
                # values to be same across the row, or column.
                # and exit the loop because a single-mismatch is sufficient 
                # to confirm that all elements are not same.
                result = False
                break
        main_idx += 1
    return result

def cols_have_same_values(self, item, item_x, item_y):
    """
    Check if any of the columns have same values

    params

    - item_x int: The row of the matrix in which item has been inserted.
    - item_y int: The column of the matrix in which the item has been inserted.
    - item int: The latest integer inserted into the matrix at row-index = item_x, and column-index = item_y. 
    """
    axis = 1
    return self.have_same_val(axis, item, item_x, item_y)