把之前案例中两个国家的数据方法一起来研究分析，那么应该怎么做？
(数据格式为[[点击量，点赞数，不喜欢数，评论数]…])
import numpy as np
t1 = np.loadtxt("./youtube_video_data/US_video_data_numbers.csv", delimiter=",", dtype="int")
t2 = np.loadtxt("./youtube_video_data/GB_video_data_numbers.csv", delimiter=",", dtype="int")
# US 0
# GB 1
US = np.array([0] * len(t1)).reshape(len(t1[:, 0]), 1)
GB = np.array([1] * len(t2)).reshape(len(t2[:, 0]), 1)
t1 = np.hstack((t1, US))
t2 = np.hstack((t2, GB))
t = np.vstack((t1, t2))
print(t)
