Pandas DataFrame的合并

append

df_appended = df1.append(df_new, ignore_index=True)#默认为False

merge

df_appended.merge(df2, on='date', how='outer')#左连接left右连接right内连接inner外连接

join

df1.join(df2, lsuffix='A', rsuffix='B')#join连接方法


df1.set_index('date').join(df2.set_index('date'))#df1索引变为date


df1.join(df2.set_index('date'), on='date')#使df1原索引不会发生变化