5

I am using the python chess module. On the website, it shows that you can check if a move is legal by using 

import chess

board = chess.Board()
move = input("Enter a chess move: ")
if move in board.legal_moves:
    # Some code to do if the move is a legal move

However, I want to be able to get a move from board.legal_moves. When I try this:

print(board.legal_moves[0])

This returns the following error:

TypeError: 'LegalMoveGenerator' object is not subscriptable

How can I select a move as if I were using a list? Then, how would I use the selection as a move?

Justin Cheng
  • 153
  • 1
  • 8

3 Answers3

10

The board.legal_moves object is a generator, or more specifically a LegalMoveGenerator. You can iterate over that object and it will yield something with each iteration. You can convert it to a list with list(board.legal_moves) and then index it as normal.

import chess
board = chess.Board()
legal_moves = list(board.legal_moves)
legal_moves[0]  # Move.from_uci('g1h3')
jkr
  • 17,119
  • 2
  • 42
  • 68
9

Generate a list from the generator.

legal_moves = list(board.legal_moves)

Legal moves is now a list.

print(legal_moves)

[Move.from_uci('g1h3'), Move.from_uci('g1f3'), Move.from_uci('b1c3'),
 Move.from_uci('b1a3'), Move.from_uci('h2h3'), Move.from_uci('g2g3'), 
 Move.from_uci('f2f3'), Move.from_uci('e2e3'), Move.from_uci('d2d3'), 
 Move.from_uci('c2c3'), Move.from_uci('b2b3'), Move.from_uci('a2a3'), 
 Move.from_uci('h2h4'), Move.from_uci('g2g4'), Move.from_uci('f2f4'), 
 Move.from_uci('e2e4'), Move.from_uci('d2d4'), Move.from_uci('c2c4'), 
 Move.from_uci('b2b4'), Move.from_uci('a2a4')]
DarrylG
  • 16,732
  • 2
  • 17
  • 23
0

Just use editing and eval function:

import chess # Import chess

board = chess.Board() # Create chess board

moves_t = str(board.legal_moves)[37:-1] # Get the tuple as string
moves_t = moves_t.replace(", ", "', '") # Converting all the SAN names into strings
moves_t = moves_t.replace("(", "('")
moves_t = moves_t.replace(")", "')")
moves_t = eval(moves_t) # Using eval function to turn into tuple
moves = [] # Creates list to store values
for i in moves_t: # Go through all values
    moves.append(i) # Add them to empty list

Though this may be bad, it is possible.

Hacker 827
  • 11
  • 5