如何使用matplotlib動畫一組點？

Question

我有生命的實施康威的遊戲新作：

def neighbors(point): 
    x, y = point 
    for i, j in itertools.product(range(-1, 2), repeat=2): 
     if any((i, j)): 
      yield (x + i, y + j) 

def advance(board): 
    newstate = set() 
    recalc = board | set(itertools.chain(*map(neighbors, board))) 

    for point in recalc: 
     count = sum((neigh in board) 
       for neigh in neighbors(point)) 
     if count == 3 or (count == 2 and point in board): 
      newstate.add(point) 

    return newstate 

我想以可視化的結果，所以我試圖從Matplotlib animation example修改給出的例子：

glider = set([(0, 0), (1, 0), (2, 0), (0, 1), (1, 2)]) 

fig, ax = plt.subplots() 

x, y = zip(*glider) 
mat, = ax.plot(x, y, 'o') 

def animate(i): 
    glider = advance(glider) 
    x, y = zip(*glider) 
    mat.set_data(x, y) 
    return mat, 

ani = animation.FuncAnimation(fig, animate, interval=50) 
plt.show() 

但只是繪製the initial points。

Answer 1

您擁有的代碼實際上應該會產生錯誤。問題在於您在分配之前先參考glider。

注意python函數中變量的局部範圍。例如。嘗試

a = 0 
def f(): 
    a = a + 1 
f() 

這會給你同樣的錯誤。

在您的康威生命遊戲代碼中，您可以通過在全球範圍內提供glider來避開此問題，即global glider。另外請確保您的軸限制允許看到動畫。

完整的示例：

import itertools 
import matplotlib.pyplot as plt 
import matplotlib.animation as animation 

def neighbors(point): 
    x, y = point 
    for i, j in itertools.product(range(-1, 2), repeat=2): 
     if any((i, j)): 
      yield (x + i, y + j) 

def advance(board): 
    newstate = set() 
    recalc = board | set(itertools.chain(*map(neighbors, board))) 

    for point in recalc: 
     count = sum((neigh in board) 
       for neigh in neighbors(point)) 
     if count == 3 or (count == 2 and point in board): 
      newstate.add(point) 

    return newstate 

glider = set([(0, 0), (1, 0), (2, 0), (0, 1), (1, 2)]) 

fig, ax = plt.subplots() 

x, y = zip(*glider) 
mat, = ax.plot(x, y, 'o') 

def animate(i): 
    global glider 
    glider = advance(glider) 
    x, y = zip(*glider) 
    mat.set_data(x, y) 
    return mat, 

ax.axis([-15,5,-15,5]) 
ani = animation.FuncAnimation(fig, animate, interval=50) 
plt.show()