I want to sequentially print the moves (one string per move at a time) from a game I read (using the python-chess library) from a text file.
So, say I have a pgn file with a game that has the following moves…
1. f3 e5 2. g4 Qh4#
… I would like to iterate through the moves and print them one by one (using a for loop or similar), showing
I found the documentation for python-chess here: https://python-chess.readthedocs.io/en/latest/
From the documentation I understand that
But I find this kind of documentation hard to read and would be greatly helped with examples.
What I managed to do is read a game from a pgn file and print all the moves in one go (as opposed to one by one) using the variation method.
import chess.pgn pgn = open('I:myfile.pgn') my_game = chess.pgn.read_game(pgn) print(my_game.variation(0))
Iterating over mainline moves
The documentation for
chess.pgn.read_game() has an example for iterating over moves. To convert the moves back to standard algebraic notation, the position is needed for context, so we additionally make all the moves on a
import chess.pgn pgn = open("test.pgn") game = chess.pgn.read_game(pgn) board = game.board() for move in game.mainline_moves(): print(board.san(move)) board.push(move)
The above example parses the entire game into a data structure (
game: chess.pgn.Game). Visitors allow skipping that intermediate representation, which can be useful to use a custom data structure instead, or as an optimization. But that seems overkill here.
Nonetheless, for completeness:
import chess.pgn class PrintMovesVisitor(chess.pgn.BaseVisitor): def visit_move(self, board, move): print(board.san(move)) def result(self): return None pgn = open("test.pgn") result = chess.pgn.read_game(pgn, Visitor=PrintMovesVisitor)
Note that this also traverses side variations in PGN order.