Generate Chess Board Diagram From An Array Of Positions In Python?

I have an array which corresponds to the positions of pieces on a chessboard, like so: ['em', 'bn', 'em', 'wr', 'em', 'wp', 'em', 'em'] ['br', 'em', 'bp', 'em', 'em', 'bn', 'wn', '

Solution 1:

It is not difficult to convert your representation to a standard one. For example, you can convert to FEN with a function like this:

import io

def board_to_fen(board):
    # Use StringIO to build string more efficiently than concatenating
    with io.StringIO() as s:
        for row in board:
            empty = 0for cell in row:
                c = cell[0]
                if c in ('w', 'b'):
                    ifempty > 0:
                        s.write(str(empty))
                        empty = 0
                    s.write(cell[1].upper() if c == 'w'else cell[1].lower())
                else:
                    empty += 1ifempty > 0:
                s.write(str(empty))
            s.write('/')
        # Move one position back to overwrite last '/'
        s.seek(s.tell() - 1)
        # If you do not have the additional information choose what to put
        s.write(' w KQkq - 0 1')
        return s.getvalue()

Testing it on some board data:

board = [
    ['bk', 'em', 'em', 'em', 'em', 'em', 'em', 'em'],
    ['em', 'bn', 'em', 'wr', 'em', 'wp', 'em', 'em'],
    ['br', 'em', 'bp', 'em', 'em', 'bn', 'wn', 'em'],
    ['em', 'em', 'bp', 'bp', 'bp', 'em', 'wp', 'bp'],
    ['bp', 'bp', 'em', 'bp', 'wn', 'em', 'wp', 'em'],
    ['em', 'em', 'em', 'em', 'em', 'em', 'em', 'em'],
    ['em', 'em', 'em', 'wk', 'em', 'em', 'em', 'em'],
    ['em', 'em', 'em', 'em', 'em', 'em', 'em', 'em'],
]
print(board_to_fen(board))
# k7/1n1R1P2/r1p2nN1/2ppp1Pp/pp1pN1P1/8/3K4/8 w KQkq - 0 1

Visualizing the FEN string for example in Chess.com produces:

Solution 2:

Alternative, a little more functional approach to converting the board into FEN:

#!/usr/bin/env python3from more_itertools import run_length


defconvert_cell(value):
    if value == 'em':
        returnNoneelse:
        color, piece = value
        return piece.upper() if color == 'w'else piece.lower()


defconvert_rank(rank):
    return''.join(
        value * count if value elsestr(count)
        for value, count in run_length.encode(map(convert_cell, rank))
    )


deffen_from_board(board):
    return'/'.join(map(convert_rank, board)) + ' w KQkq - 0 1'defmain():
    board = [
        ['bk', 'em', 'em', 'em', 'em', 'em', 'em', 'em'],
        ['em', 'bn', 'em', 'wr', 'em', 'wp', 'em', 'em'],
        ['br', 'em', 'bp', 'em', 'em', 'bn', 'wn', 'em'],
        ['em', 'em', 'bp', 'bp', 'bp', 'em', 'wp', 'bp'],
        ['bp', 'bp', 'em', 'bp', 'wn', 'em', 'wp', 'em'],
        ['em', 'em', 'em', 'em', 'em', 'em', 'em', 'em'],
        ['em', 'em', 'em', 'wk', 'em', 'em', 'em', 'em'],
        ['em', 'em', 'em', 'em', 'em', 'em', 'em', 'em'],
    ]
    print(fen_from_board(board))


if __name__ == '__main__':
    main()