Coderetreat: Java 8 vs Scala http://ldn.lv/events/138303652/ (Python quietly sneaks in)

gameoflife1.py

import time

def cell_transition(alive, neighbour_count):
    return neighbour_count in (2, 3) if alive else neighbour_count == 3


class RectField(object):

    def __init__(self, size, cells):
        self.size = size 
        self.cells = cells

    @classmethod
    def empty_field(cls, size):
        return cls(size, [0]*(size**2))

    def xy(self, n):
        return n % self.size, n // self.size

    def neighbour_indexes(self, n):
        x, y = self.xy(n)
        return [i + j * self.size for i, j in [
                (x - 1, y + 1), (x, y + 1), (x + 1, y + 1),
                (x - 1, y),                 (x + 1, y),
                (x - 1, y - 1), (x, y - 1), (x + 1, y - 1),
            ] if 0 <= i < self.size and 0 <= j < self.size]

    def cell_neighbours(self, n):
        return sum(self.cells[i] for i in self.neighbour_indexes(n))

    def next(self):
        next_cells = [
            cell_transition(cell, self.cell_neighbours(n))
            for n, cell in enumerate(self.cells)
        ]
        return self.__class__(self.size, next_cells)

    def __str__(self):
        return ''.join(
            ('X' if cell else '.') + ('\n' if x == self.size - 1 else '')
            for cell, x in ((cell, self.xy(n)[0]) for n, cell in enumerate(self.cells))
        )

    @classmethod
    def field_from_text(cls):
        text = """
            .....
            ..X..
            ..X..
            ..X..
            .....
            """
        return cls(5, [c == 'X' for c in text if c in '.X'])


if __name__ == "__main__":
    field = RectField.field_from_text()
    while True:
        print(field)
        time.sleep(1)
        field = field.next()