((3,4))*0,columns=['a','b','c','d'])
df2 = pd.DataFrame(np.ones((3,4))*1,columns=['a','b','c','d'])
df3...=True)#0表示行合并,1表示列合并,ingnore_index重置序列index index变为1-8
print(res)
#join合并
df1 = pd.DataFrame(np.ones(...(3,4))*0,columns=['a','b','c','d'],index=[1,2,3])
df2 = pd.DataFrame(np.ones((3,4))*1,columns=['a','b...((3,4))*0,columns=['a','b','c','d'])
df2 = pd.DataFrame(np.ones((3,4))*1,columns=['a','b','c','d'])
df3...= pd.DataFrame(np.ones((3,4))*2,columns=['a','b','c','d'])
s1 = pd.Series([1,2,3,4],index=['a','b','