我想绘制不同视角的3D图，每个图都有一组相同的数据，根据组的不同颜色。但是下面的方法似乎只绘制最后一组数据，而不是保留前面的组。

fig = plt.figure()
# group_id is a group-id map, eg {'A': 0, 'B': 1, ...}
for k, v in group_id.items():
    # data_id indicates id of each data
    subset_idx = data_id == v  # obtain idx of data belonging to group k
    d = data[subset_idx]  # get the data subset
    for i, angle in enumerate([45, 90, 135, 180]):
        ax = fig.add_subplot(1, 4, i + 1, projection='3d')
        ax.view_init(azim=angle)
        ax.scatter(d[:, 0], d[:, 1], d[:, 2], c=colors[v], label=k)

该示例会遇到一个警告：

MatplotlibDeprecationWarning:
Adding an axes using the same arguments as a previous axes currently 
reuses the earlier instance.  In a future version, a new instance will 
always be created and returned.  Meanwhile, this warning can be 
suppressed, and the future behavior ensured, by passing a unique label 
to each axes instance.
  "Adding an axes using the same arguments as a previous axes "

这应该不会引起任何严重的问题。然而，结果似乎只绘制了最后一组数据（group_id中的最后一项），这表明ax = fig.add_subplot可能已经创建了与警告中的描述不匹配的新轴。对我来说更令人困惑的是，2d plot的方法完全相同（尽管它给出了相同的警告）。