pandas 设置多重索引_pandas dataframe多重索引常用操作

增加(创建)

df1=pd.DataFrame(np.arange(12).reshape(4,3),index=[list("AABB"),[1,2,1,2]],columns=[list("XXY"),[10,11,10]]) df1.index=pd.MultiIndex.from_arrays([list("AABB"),[3,4,3,4]],names=["AB","num"])

df = df.set_index(['class','id'])

修改

df1.columns.names=['XY','sum']

df1.index.names=['AB','num']

df1.index=pd.MultiIndex.from_arrays([list("AABB"),[3,4,3,4]],names=["AB","num"])

df1.swaplevel('AB','num')

查询

df.loc[('A',slice(None)),:]

df2.loc[('语文',slice(None)),:]

UnsortedIndexError: 'MultiIndex Slicing requires the index to be fully lexsorted tuple len (2), lexsort depth (0)'

对index排序后切片选择index

df2 = df2.sort_index(level='课程')

df2.loc[('语文',slice(None)),:]

获取相应内容

.get_level_values()    Index    level    int/name: 获取对应级别的索引

参考:https://blog.youkuaiyun.com/weixin_38168620/article/details/80071141

https://blog.youkuaiyun.com/PIPIXIU/article/details/80232805

https://www.cnblogs.com/P--K/p/8672563.html