I am working on a simple cheat detection script to find if a user used one of the top engine moves in a game, so I found this great python-chess library Additionally, I found this example to getting the moves score. But that topic is an old version of the lib so I tried to update the script. However, I keep getting errors, and I don't know how to get the scores in the right way.

import asyncio
import chess
#import chess.uci
import chess.engine
import chess.pgn
import io
#Let's try our code with the starting position of chess:

fen = 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1'
board = chess.Board(fen)

#Now make sure you give the correct location for your stockfish engine file
#...in the line follows: e.g., /home/.../stockfish_6_x64

engine = chess.engine.SimpleEngine.popen_uci('/home/shar/Desktop/cheat detect python/stockfish-10-linux/Linux/stockfish_10_x64')

if board.turn: print( 'White to move');
else: print( 'black to move');

for el in board.legal_moves:

    pgn = io.StringIO(board.san(el))

    thnwpgntofen = chess.pgn.read_game(pgn);
    nwinfo = engine.analysis(thnwpgntofen.board());



I get this error after running my code:

Traceback (most recent call last): File "prntengmv.py", line 37, in print(nwinfo["score"]) TypeError: 'SimpleAnalysisResult' object is not subscriptable

  • The updated version is added here.
    – Ellie
    Jan 7, 2020 at 4:37

1 Answer 1


As per: https://python-chess.readthedocs.io/en/latest/engine.html#indefinite-or-infinite-analysis

engine.analysis(board) now returns an AnalysisResult object, which has the property info that you want.

So instead of:

nwinfo = engine.analysis(...)

You would loop over info in the AnalysisResult, and print the score property from each element:

with engine.analysis(...) as analysis:
    for info in analysis:

However, your use case looks like it may benefit from engine.analyse more than engine.analysis.

  • thanks now the error gones but i getting a hundreds of outputs
    – shar
    Aug 7, 2019 at 14:25
  • This is because engine.analysis gives an indefinite analysis - i.e. the engine will keep analyzing forever. You can resolve this by setting some termination condition and exiting the loop, or you could use engine.analyse instead, which allows you to set a limit beforehand. Check the documentation link in my answer.
    – konsolas
    Aug 7, 2019 at 14:32
  • every time i run my script i getting a different score are for the same moves are that normal ?
    – shar
    Aug 7, 2019 at 14:46
  • Engines aren't wholly deterministic. As long as the scores are reasonable each time, it's probably correct.
    – konsolas
    Aug 7, 2019 at 14:58

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