Initial Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

LLM Generation

Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

Output

To print the PGN notation for all prefixes of a game in python-chess, you can create a function called `print_all_prefixes(game)`. Here's how you can implement this function: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        prefix_game = chess.pgn.Game()
        node = prefix_game
        
        # Copy game headers
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Add moves for this prefix
        for move in moves[:i]:
            node = node.add_variation(move)
            board.push(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        exporter = chess.pgn.FileExporter(output)
        
        # Export the prefix game to PGN format
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)
        
        # Reset the board for the next iteration
        board.reset()
This function does the following: 1. It creates a list of all moves in the main line of the game. 2. It iterates through all possible prefixes, from 0 moves to the full game. 3. For each prefix, it creates a new `chess.pgn.Game()` object. 4. It copies the headers from the original game to maintain metadata. 5. It adds the moves for the current prefix to the new game object. 6. It uses a `StringIO` object and `FileExporter` to generate the PGN notation for the prefix. 7. It prints the PGN notation for each prefix, along with a header indicating the number of moves. 8. It resets the board after each prefix to prepare for the next iteration. This function will print the PGN notation for all prefixes of the game, starting from an empty game (just headers) and progressively adding moves until it reaches the full game. Each prefix will be separated by a line of dashes for clarity.

Extract Code

I extracted the following code from that output: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        prefix_game = chess.pgn.Game()
        node = prefix_game
        
        # Copy game headers
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Add moves for this prefix
        for move in moves[:i]:
            node = node.add_variation(move)
            board.push(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        exporter = chess.pgn.FileExporter(output)
        
        # Export the prefix game to PGN format
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)
        
        # Reset the board for the next iteration
        board.reset()

Run Code Interpreter

Running the following program: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        prefix_game = chess.pgn.Game()
        node = prefix_game
        
        # Copy game headers
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Add moves for this prefix
        for move in moves[:i]:
            node = node.add_variation(move)
            board.push(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        exporter = chess.pgn.FileExporter(output)
        
        # Export the prefix game to PGN format
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)
        
        # Reset the board for the next iteration
        board.reset()



import io
import chess.pgn
print_all_prefixes(chess.pgn.read_game(io.StringIO('1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 15. Bc4 Nxc3')))
And got the output: 
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Prefix with 0 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
*</p>
<hr />
<p>Prefix with 1 move:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 *</p>
<hr />
<p>Prefix with 2 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 *</p>
<hr />
<p>Prefix with 3 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 *</p>
<hr />
<p>Prefix with 4 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 *</p>
<hr />
<p>Prefix with 5 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 *</p>
<hr />
<p>Prefix with 6 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 *</p>
<hr />
<p>Prefix with 7 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 *</p>
<hr />
<p>Prefix with 8 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O *</p>
<hr />
<p>Prefix with 9 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 *</p>
<hr />
<p>Prefix with 10 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 *</p>
<hr />
<p>Prefix with 11 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 *</p>
<hr />
<p>Prefix with 12 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 *</p>
<hr />
<p>Prefix with 13 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 *</p>
<hr />
<p>Prefix with 14 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 *</p>
<hr />
<p>Prefix with 15 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
*</p>
<hr />
<p>Prefix with 16 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 *</p>
<hr />
<p>Prefix with 17 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 *</p>
<hr />
<p>Prefix with 18 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 *</p>
<hr />
<p>Prefix with 19 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 *</p>
<hr />
<p>Prefix with 20 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 *</p>
<hr />
<p>Prefix with 21 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 *</p>
<hr />
<p>Prefix with 22 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 *</p>
<hr />
<p>Prefix with 23 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 *</p>
<hr />
<p>Prefix with 24 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 *</p>
<hr />
<p>Prefix with 25 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 *</p>
<hr />
<p>Prefix with 26 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 *</p>
<hr />
<p>Prefix with 27 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 *</p>
<hr />
<p>Prefix with 28 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
*</p>
<hr />
<p>Prefix with 29 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
15. Bc4 *</p>
<hr />
<p>Prefix with 30 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
15. Bc4 Nxc3 *</p>
<hr />
<p>

PyFunc

Resulting in output: True

Initial Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

LLM Generation

Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

Output

Here's a Python function that prints the PGN notation for all prefixes of a given chess game using the python-chess library: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        prefix_game = chess.pgn.Game()
        prefix_game.setup(board)
        node = prefix_game
        
        for move in moves[:i]:
            node = node.add_variation(move)
        
        exporter = chess.pgn.StringExporter(headers=True, variations=False, comments=False)
        pgn_string = prefix_game.accept(exporter)
        
        print(f"Prefix of length {i}:")
        print(pgn_string)
        print()  # Empty line for better readability between prefixes
This function does the following: 1. It takes a `game` object as input, which is assumed to be a chess game loaded using `chess.pgn.read_game()`. 2. It extracts the initial board position and the list of moves from the game. 3. It then iterates through all possible prefixes of the game, from 0 moves (just the initial position) to the full game. 4. For each prefix length, it creates a new game object, sets up the initial board, and adds the moves for that prefix. 5. It uses a `StringExporter` to convert the prefix game to a PGN string. The `headers=True` argument ensures that game metadata is included, while `variations=False` and `comments=False` exclude variations and comments for simplicity. 6. Finally, it prints the PGN string for each prefix, along with a label indicating the prefix length. This function will print the PGN notation for all prefixes of the game, starting from just the initial position and gradually including more moves until it reaches the full game. Each prefix will be displayed with its corresponding length and full PGN notation, including headers.

Extract Code

I extracted the following code from that output: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        prefix_game = chess.pgn.Game()
        prefix_game.setup(board)
        node = prefix_game
        
        for move in moves[:i]:
            node = node.add_variation(move)
        
        exporter = chess.pgn.StringExporter(headers=True, variations=False, comments=False)
        pgn_string = prefix_game.accept(exporter)
        
        print(f"Prefix of length {i}:")
        print(pgn_string)
        print()  # Empty line for better readability between prefixes

Run Code Interpreter

Running the following program: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        prefix_game = chess.pgn.Game()
        prefix_game.setup(board)
        node = prefix_game
        
        for move in moves[:i]:
            node = node.add_variation(move)
        
        exporter = chess.pgn.StringExporter(headers=True, variations=False, comments=False)
        pgn_string = prefix_game.accept(exporter)
        
        print(f"Prefix of length {i}:")
        print(pgn_string)
        print()  # Empty line for better readability between prefixes




import io
import chess.pgn
print_all_prefixes(chess.pgn.read_game(io.StringIO('1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 15. Bc4 Nxc3')))
And got the output: Prefix of length 0: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] * Prefix of length 1: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 * Prefix of length 2: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 * Prefix of length 3: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 * Prefix of length 4: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 * Prefix of length 5: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 * Prefix of length 6: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 * Prefix of length 7: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 * Prefix of length 8: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O * Prefix of length 9: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 * Prefix of length 10: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 * Prefix of length 11: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 * Prefix of length 12: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 * Prefix of length 13: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 * Prefix of length 14: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 * Prefix of length 15: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 * Prefix of length 16: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 * Prefix of length 17: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 * Prefix of length 18: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 * Prefix of length 19: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 * Prefix of length 20: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 * Prefix of length 21: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 * Prefix of length 22: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 * Prefix of length 23: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 * Prefix of length 24: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 * Prefix of length 25: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 * Prefix of length 26: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 * Prefix of length 27: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 * Prefix of length 28: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 * Prefix of length 29: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 15. Bc4 * Prefix of length 30: [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] 1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 15. Bc4 Nxc3 *

PyFunc

Resulting in output: True

Initial Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

LLM Generation

Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

Output

Here's a Python function that prints the PGN notation for all prefixes of a given chess game using the python-chess library: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        # Create a new game object for the prefix
        prefix_game = chess.pgn.Game()
        
        # Copy the headers from the original game
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Set up the initial position
        prefix_game.setup(board)
        
        # Add moves to the prefix game
        node = prefix_game
        for move in moves[:i]:
            node = node.add_variation(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)
This function does the following: 1. It takes a `game` object as input, which is assumed to be a chess game loaded using `chess.pgn.read_game()`. 2. It extracts the initial board position and the list of moves from the game. 3. It iterates through all possible prefixes of the game, from 0 moves to the full game. 4. For each prefix: - It creates a new game object. - It copies the headers from the original game. - It sets up the initial board position. - It adds the moves for this prefix. - It exports the prefix game to PGN format using a StringIO object. - It prints the PGN notation for this prefix. 5. It separates each prefix output with a line of dashes for clarity. This function will print the PGN notation for all prefixes of the game, starting from the initial position (0 moves) up to the complete game. Each prefix will include the full headers and the moves up to that point in standard PGN format.

Extract Code

I extracted the following code from that output: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        # Create a new game object for the prefix
        prefix_game = chess.pgn.Game()
        
        # Copy the headers from the original game
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Set up the initial position
        prefix_game.setup(board)
        
        # Add moves to the prefix game
        node = prefix_game
        for move in moves[:i]:
            node = node.add_variation(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)

Run Code Interpreter

Running the following program: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        # Create a new game object for the prefix
        prefix_game = chess.pgn.Game()
        
        # Copy the headers from the original game
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Set up the initial position
        prefix_game.setup(board)
        
        # Add moves to the prefix game
        node = prefix_game
        for move in moves[:i]:
            node = node.add_variation(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)



import io
import chess.pgn
print_all_prefixes(chess.pgn.read_game(io.StringIO('1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 15. Bc4 Nxc3')))
And got the output: 
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Prefix with 0 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
*</p>
<hr />
<p>Prefix with 1 move:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 *</p>
<hr />
<p>Prefix with 2 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 *</p>
<hr />
<p>Prefix with 3 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 *</p>
<hr />
<p>Prefix with 4 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 *</p>
<hr />
<p>Prefix with 5 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 *</p>
<hr />
<p>Prefix with 6 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 *</p>
<hr />
<p>Prefix with 7 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 *</p>
<hr />
<p>Prefix with 8 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O *</p>
<hr />
<p>Prefix with 9 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 *</p>
<hr />
<p>Prefix with 10 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 *</p>
<hr />
<p>Prefix with 11 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 *</p>
<hr />
<p>Prefix with 12 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 *</p>
<hr />
<p>Prefix with 13 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 *</p>
<hr />
<p>Prefix with 14 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 *</p>
<hr />
<p>Prefix with 15 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
*</p>
<hr />
<p>Prefix with 16 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 *</p>
<hr />
<p>Prefix with 17 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 *</p>
<hr />
<p>Prefix with 18 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 *</p>
<hr />
<p>Prefix with 19 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 *</p>
<hr />
<p>Prefix with 20 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 *</p>
<hr />
<p>Prefix with 21 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 *</p>
<hr />
<p>Prefix with 22 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 *</p>
<hr />
<p>Prefix with 23 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 *</p>
<hr />
<p>Prefix with 24 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 *</p>
<hr />
<p>Prefix with 25 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 *</p>
<hr />
<p>Prefix with 26 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 *</p>
<hr />
<p>Prefix with 27 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 *</p>
<hr />
<p>Prefix with 28 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
*</p>
<hr />
<p>Prefix with 29 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
15. Bc4 *</p>
<hr />
<p>Prefix with 30 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
15. Bc4 Nxc3 *</p>
<hr />
<p>

PyFunc

Resulting in output: True

Initial Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

LLM Generation

Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

Output

Here's a Python function that prints the PGN notation for all prefixes of a given chess game using python-chess: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        # Create a new game object for each prefix
        prefix_game = chess.pgn.Game()
        
        # Copy the headers from the original game
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Add moves to the prefix game
        node = prefix_game
        for move in moves[:i]:
            node = node.add_variation(move)
            
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)
This function does the following: 1. It takes a `game` object as input, which is assumed to be a chess game loaded using `chess.pgn.read_game()`. 2. It extracts the list of moves from the game's mainline. 3. It iterates through all possible prefixes of the game, from 0 moves to the full game. 4. For each prefix: - It creates a new game object. - It copies the headers from the original game to maintain metadata. - It adds the moves for this prefix to the new game object. - It exports the prefix game to PGN format using a StringIO object to capture the output. - It prints the PGN notation for this prefix. 5. Each prefix is separated by a line of dashes for better readability. This function will print the PGN notation for the game with 0 moves (just the initial position), then with the first move, then the first two moves, and so on until it prints the full game. Each prefix will include the full headers from the original game.

Extract Code

I extracted the following code from that output: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        # Create a new game object for each prefix
        prefix_game = chess.pgn.Game()
        
        # Copy the headers from the original game
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Add moves to the prefix game
        node = prefix_game
        for move in moves[:i]:
            node = node.add_variation(move)
            
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)

Run Code Interpreter

Running the following program: 

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import chess.pgn
import io

def print_all_prefixes(game):
    board = game.board()
    moves = list(game.mainline_moves())
    
    for i in range(len(moves) + 1):
        # Create a new game object for each prefix
        prefix_game = chess.pgn.Game()
        
        # Copy the headers from the original game
        for key, value in game.headers.items():
            prefix_game.headers[key] = value
        
        # Add moves to the prefix game
        node = prefix_game
        for move in moves[:i]:
            node = node.add_variation(move)
            
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for this prefix
        print(f"Prefix with {i} move{'s' if i != 1 else ''}:")
        print(output.getvalue())
        print("-" * 40)



import io
import chess.pgn
print_all_prefixes(chess.pgn.read_game(io.StringIO('1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 15. Bc4 Nxc3')))
And got the output: 
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Prefix with 0 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
*</p>
<hr />
<p>Prefix with 1 move:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 *</p>
<hr />
<p>Prefix with 2 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 *</p>
<hr />
<p>Prefix with 3 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 *</p>
<hr />
<p>Prefix with 4 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 *</p>
<hr />
<p>Prefix with 5 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 *</p>
<hr />
<p>Prefix with 6 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 *</p>
<hr />
<p>Prefix with 7 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 *</p>
<hr />
<p>Prefix with 8 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O *</p>
<hr />
<p>Prefix with 9 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 *</p>
<hr />
<p>Prefix with 10 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 *</p>
<hr />
<p>Prefix with 11 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 *</p>
<hr />
<p>Prefix with 12 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 *</p>
<hr />
<p>Prefix with 13 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 *</p>
<hr />
<p>Prefix with 14 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 *</p>
<hr />
<p>Prefix with 15 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
*</p>
<hr />
<p>Prefix with 16 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 *</p>
<hr />
<p>Prefix with 17 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 *</p>
<hr />
<p>Prefix with 18 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 *</p>
<hr />
<p>Prefix with 19 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 *</p>
<hr />
<p>Prefix with 20 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 *</p>
<hr />
<p>Prefix with 21 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 *</p>
<hr />
<p>Prefix with 22 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 *</p>
<hr />
<p>Prefix with 23 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 *</p>
<hr />
<p>Prefix with 24 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 *</p>
<hr />
<p>Prefix with 25 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 *</p>
<hr />
<p>Prefix with 26 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 *</p>
<hr />
<p>Prefix with 27 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 *</p>
<hr />
<p>Prefix with 28 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
*</p>
<hr />
<p>Prefix with 29 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
15. Bc4 *</p>
<hr />
<p>Prefix with 30 moves:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4
Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6
15. Bc4 Nxc3 *</p>
<hr />
<p>

PyFunc

Resulting in output: True

Initial Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

LLM Generation

Query

In python-chess I have a game = chess.pgn.read_game(pgn). How do I print the PGN notation for all prefixes of this game? Call your function print_all_prefixes(game). Do not give example code for how to run it.

Output

Here's a Python function that prints the PGN notation for all prefixes of a given chess game using the python-chess library: 

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import chess.pgn
import io

def print_all_prefixes(game):
    # Create a new game object to build prefixes
    prefix_game = chess.pgn.Game()
    prefix_game.headers = game.headers.copy()

    # Iterate through all moves in the original game
    for i, move in enumerate(game.mainline_moves()):
        # Add the move to the prefix game
        node = prefix_game.add_variation(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the current prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for the current prefix
        print(f"Prefix {i + 1}:")
        print(output.getvalue())
        print("-" * 40)  # Separator between prefixes

        # Update the prefix game to the last node
        prefix_game = node.game()
This function does the following: 1. It creates a new `prefix_game` object to build the prefixes incrementally. 2. It copies the headers from the original game to maintain metadata. 3. It iterates through all moves in the original game's mainline. 4. For each move, it adds the move to the `prefix_game`. 5. It then exports the current state of `prefix_game` to PGN format using a `StringIO` object and the `FileExporter` from python-chess. 6. It prints the PGN notation for the current prefix, along with a prefix number and a separator. 7. Finally, it updates the `prefix_game` to the last node, preparing for the next iteration. This function will print the PGN notation for all prefixes of the game, starting from the initial position and adding one move at a time until the full game is printed.

Extract Code

I extracted the following code from that output: 

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import chess.pgn
import io

def print_all_prefixes(game):
    # Create a new game object to build prefixes
    prefix_game = chess.pgn.Game()
    prefix_game.headers = game.headers.copy()

    # Iterate through all moves in the original game
    for i, move in enumerate(game.mainline_moves()):
        # Add the move to the prefix game
        node = prefix_game.add_variation(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the current prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for the current prefix
        print(f"Prefix {i + 1}:")
        print(output.getvalue())
        print("-" * 40)  # Separator between prefixes

        # Update the prefix game to the last node
        prefix_game = node.game()

Run Code Interpreter

Running the following program: 

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import chess.pgn
import io

def print_all_prefixes(game):
    # Create a new game object to build prefixes
    prefix_game = chess.pgn.Game()
    prefix_game.headers = game.headers.copy()

    # Iterate through all moves in the original game
    for i, move in enumerate(game.mainline_moves()):
        # Add the move to the prefix game
        node = prefix_game.add_variation(move)
        
        # Create a string IO object to capture the PGN output
        output = io.StringIO()
        
        # Export the current prefix game to PGN format
        exporter = chess.pgn.FileExporter(output)
        prefix_game.accept(exporter)
        
        # Print the PGN for the current prefix
        print(f"Prefix {i + 1}:")
        print(output.getvalue())
        print("-" * 40)  # Separator between prefixes

        # Update the prefix game to the last node
        prefix_game = node.game()



import io
import chess.pgn
print_all_prefixes(chess.pgn.read_game(io.StringIO('1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 15. Bc4 Nxc3')))
And got the output: 
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Prefix 1:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 *</p>
<hr />
<p>Prefix 2:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) *</p>
<hr />
<p>Prefix 3:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) *</p>
<hr />
<p>Prefix 4:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) ( 1. gxg6 ) *</p>
<hr />
<p>Prefix 5:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) ( 1. gxg6 ) ( 1. Nc3 ) *</p>
<hr />
<p>Prefix 6:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) ( 1. gxg6 ) ( 1. Nc3 ) ( 1. Bxg7 ) *</p>
<hr />
<p>Prefix 7:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) ( 1. gxg6 ) ( 1. Nc3 ) ( 1. Bxg7 ) ( 1. d4 ) *</p>
<hr />
<p>Prefix 8:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) ( 1. gxg6 ) ( 1. Nc3 ) ( 1. Bxg7 ) ( 1. d4 ) ( 1.
O-O ) *</p>
<hr />
<p>Prefix 9:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) ( 1. gxg6 ) ( 1. Nc3 ) ( 1. Bxg7 ) ( 1. d4 ) ( 1.
O-O ) ( 1. Bf4 ) *</p>
<hr />
<p>Prefix 10:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) ( 1. gxg6 ) ( 1. Nc3 ) ( 1. Bxg7 ) ( 1. d4 ) ( 1.
O-O ) ( 1. Bf4 ) ( 1. dxd5 ) *</p>
<hr />
<p>Prefix 11:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. Nf3 ( 1. Nxf6+ ) ( 1. c4 ) ( 1. gxg6 ) ( 1. Nc3 ) ( 1. Bxg7 ) ( 1. d4 ) ( 1.
O-O ) ( 1. Bf4 ) ( 1. dxd5 ) ( 1. Qb3 ) *</p>
<hr />
<p>Traceback (most recent call last):
  File "/usr/src/app/main.py", line 34, in <module>
    print_all_prefixes(chess.pgn.read_game(io.StringIO('1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. d4 O-O 5. Bf4 d5 6. Qb3 dxc4 7. Qxc4 c6 8. e4 Nbd7 9. Rd1 Nb6 10. Qc5 Bg4 11. Bg5 Na4 12. Qa3 Nxc3 13. bxc3 Nxe4 14. Bxe7 Qb6 15. Bc4 Nxc3')))
  File "/usr/src/app/main.py", line 20, in print_all_prefixes
    prefix_game.accept(exporter)
  File "/usr/local/lib/python3.10/dist-packages/chess/pgn.py", line 883, in accept
    self.variations[0]._accept(board, visitor)
  File "/usr/local/lib/python3.10/dist-packages/chess/pgn.py", line 756, in _accept
    top.node._accept_node(parent_board, visitor)
  File "/usr/local/lib/python3.10/dist-packages/chess/pgn.py", line 733, in _accept_node
    visitor.visit_move(parent_board, self.move)
  File "/usr/local/lib/python3.10/dist-packages/chess/pgn.py", line 1403, in visit_move
    self.write_token(board.san(move) + " ")
  File "/usr/local/lib/python3.10/dist-packages/chess/<strong>init</strong>.py", line 2866, in san
    return self._algebraic(move)
  File "/usr/local/lib/python3.10/dist-packages/chess/<strong>init</strong>.py", line 2879, in _algebraic
    san = self._algebraic_and_push(move, long=long)
  File "/usr/local/lib/python3.10/dist-packages/chess/<strong>init</strong>.py", line 2884, in _algebraic_and_push
    san = self._algebraic_without_suffix(move, long=long)
  File "/usr/local/lib/python3.10/dist-packages/chess/<strong>init</strong>.py", line 2920, in _algebraic_without_suffix
    assert piece_type, f"san() and lan() expect move to be legal or null, but got {move} in {self.fen()}"
AssertionError: san() and lan() expect move to be legal or null, but got d5c4 in rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

PyFunc

Resulting in output: False