Get Location of Piece in Python-Chess

Question

I am currently building a chess game using Python-Chess, and I am trying to use the SVG module to generate SVG images of the board. One of the parameters for generating an svg is check (here), which is a "square to be marked indicating a check". However, from the docs, I couldn't find a way to figure out where the player's king is.

What I want to happen is, whenever board.is_check() I want it to generate the svg with check=, using the current location of the current player's king. How do I figure this out? Do I have to iterate through every square and check what piece is on there until I find the correct king? Or is there a function for this that I didn't see? Any help is appreciated, Thanks in advance!

You're tracking all the moves, right? Python-Chess helps maintain the board and gives hints, but you make the moves. You can get the FEN string with `board.board_fen()`. You can look up the format in the documentation. — Tim Roberts, Mar 30 '21 at 19:35
I see... the fen returns a string with piece locations. But from this string, how do I get the square where the king is (e.g. chess.E5)? — Krishnan Shankar, Mar 30 '21 at 19:37
I would probably do `for rank,row in enumerate(fen.split('/'):` / `idx = row.find('k')` / `if idx < 0: continue`. Then `idx` has the file (counting from 0), and `rank` has the row (counting from 0). — Tim Roberts, Mar 30 '21 at 19:39
So... rank 3 would be 3, and idx 5 would be f? which would give me F3? Is there some way you could get `F3` from 3 and 5? — Krishnan Shankar, Mar 30 '21 at 19:47
`rank == 3` would be `F4`. I don't know how the square constants are made, but there must be a way. — Tim Roberts, Mar 30 '21 at 20:01
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/230558/discussion-between-krishnan-shankar-and-tim-roberts). — Krishnan Shankar, Mar 30 '21 at 20:01
No. I dislike that SO "feature" very much. I'm getting my answers from the Python-Chess documentation. — Tim Roberts, Mar 30 '21 at 20:04

score 4 · Accepted Answer · answered Mar 31 '21 at 17:06

There is a function for getting the position of the king which is documented here: https://python-chess.readthedocs.io/en/latest/core.html#chess.BaseBoard.king

Here is some example code:

import chess
board = chess.Board()
# get the current square index of the white king
king_square_index = board.king(chess.WHITE)
# get the current square name of the white king
king_square_name = chess.square_name(king_square_index)
print(king_square_name) # e1
# Move white pawn to e4
board.push_san("e4")
# Move black pawn to e5
board.push_san("e5")
# Move white king to e2
board.push_san("Ke2")
# get the current square index of the white king
king_square_index = board.king(chess.WHITE)
# get the current square name of the white king
king_square_name = chess.square_name(king_square_index)
print(king_square_name) # e2

Wow - I never noticed this! Thanks a lot! – Krishnan Shankar Mar 31 '21 at 18:09 — Krishnan Shankar, Mar 31 '21 at 18:09

Get Location of Piece in Python-Chess

1 Answers1