conway game of life

conway001.py

# conways game of life
# see https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life


startfield="""
...X............
.......XXX.....X
...............X
...............X
................
................
...X............
...X............
"""

startfield2 = """
.....
.....
.XXX.
.....
.....
"""

def display(array):
    for line in array:
        # print(line)
       print( "".join(line))


def check_startfield():
    """reads startfield into an array and returns it,
    return None if array is not rectangular"""
    length = None
    board = []
    # spielfeld einlesen
    for line in startfield.splitlines():
        if len(line.strip())==0:
            continue
        if length is None:
            length = len(line)
        if len(line) != length:
            print(f"Error: Length should be: {length} but is {len(line)}: {line}")
            return None
        board.append(list(line))
    return board

def main():
    board = check_startfield()
    if board is None:
        return
    length = len(board[0])
    height = len(board)
    print("Dimensions:",length, height)

    while True:
        display(board)
        command=input("press ENTER for next turn or q to quit >>>")
        if command=="q":
            break
        # board2 must be empty
        board2 = [["." for element in line1] for line1 in board]
        #print("empty:", board2)
        # caclulate
        #numbers = []
        for y, line in enumerate(board):
            #numberline = ""
            for x, char in enumerate(line):
                alive=0
                for dx,dy in ((1,0),(1,1),(0,1),(-1,1),(-1,0),(-1,-1),(0,-1),(1,-1)):
                    # wrap-around
                    nx = x+dx
                    ny = y+dy
                    #if nx == -1:
                    #    nx = length - 1
                    #if ny == -1:
                    #    ny = height - 1
                    if nx == length:
                        nx = 0
                    if ny == height:
                        ny = 0

                    if board[ny][nx] == "X":
                        alive += 1
                #numberline += f"{alive}"
                new = "."
                if (board[y][x]==".") and (alive == 3):
                    new = "X"
                elif (board[y][x]== "X") and (2 <= alive <= 3):
                    new = "X"

                board2[y][x]=new
        #    numbers.append(numberline)
        #print("\n".join(numbers))
        board = board2


if __name__ == "__main__":
    main()