阿喨的部落格

-------------------------------------------------------------------------------------------------數據合併concat.append
pd.concat([df1,df2,df3],axis=0,ignore_index=True)axis=0垂直合併 ignore_index=True重新編號index
pd.concat([df1,df2],join='inner') inner會刪除有nan的那行，默認join='outer'使空值呈現nan
pd.concat([df1,df2],axis=1,join_axes=[df1.index])axis=1列合併，join_axes=[df1.index]主要index以df1為主
                                                Ex:如果df1的index是1.2.3，df2是2.3.4則合併後只會有index:1.2.3
df1.append([df2,df3],ignore_index=True)將df2,df3直接加在df1後面
df1.append(pd.Series([1,2,3,4],index=['a','b','c','d']),ignore_index=True)增加單列數據
------------------------------------------------------------------------------------------------數據合併merge,one key
left=pd.DataFrame({'key':['K0','K1','K2','K3'],     right=pd.DataFrame({'key':['K0','K1','K2','K3'],
                     'A':['A0','A1','A2','A3'],                          'C':['C0','C1','C2','C3'],
                     'B':['B0','B1','B2','B3']})                         'D':['D0','D1','D2','D3']})
print(pd.merge(left,right,on='key'))