代码：
import pandas as pd
import numpy as np
df1 = pd.DataFrame(np.ones([5, 3]))
df2 = pd.DataFrame(np.ones([5, 3])*2)
print("df1 = \n", df1, "\n")
print("df2 = \n", df2, "\n")
# 上下拼接
df = pd.concat([df1, df2], axis=0)
print("df1 df2上下拼接：\n", df, "\n")
# 左右拼接
df = pd.concat([df1, df2], axis=1)
print("df1 df2左右拼接：\n", df, "\n")
