Elegant and minimalist implementation of Conway's Game of Life

conway.py

#!/usr/bin/python3

# Conway's Game of Life
# Based on Jack Diederich's implementation
# http://pyvideo.org/video/880/stop-writing-classes

from itertools import chain, product

neighbour_deltas = set(list(product([-1, 0, 1], repeat=2))) - set([(0, 0)])


def neighbour_points(point):
    x, y = point
    return ((x + dx, y + dy) for dx, dy in neighbour_deltas)


def advance(board):
    new_board = set()
    recalc = board | set(chain(*map(neighbour_points, board)))
    for point in recalc:
        count = sum(n_point in board for n_point in neighbour_points(point))
        if count == 3 or (count == 2 and point in board):
            new_board.add(point)
    return new_board


# Implementation ends here. Here is a use example:


def print_board(board, xrange=None, yrange=None):
    if xrange is None:
        xrange = min(p[0] for p in board), max(p[0] for p in board) + 1
    if yrange is None:
        yrange = min(p[1] for p in board), max(p[1] for p in board) + 1
    for y in range(*yrange):
        for x in range(*xrange):
            print('*' if (x, y) in board else ' ', end='')
        print()
    print('--')

if __name__ == '__main__':
    oscillator = set([(1, 1), (2, 1), (3, 1)])
    print_board(oscillator, (0, 4), (0, 4))
    for i in range(10):
        oscillator = advance(oscillator)
        print_board(oscillator, (0, 4), (0, 4))