Python Pandas - 多索引的交换级别

要交换MultiIndex的级别，请使用swaplevel()Pandas中的方法。要交换的级别应作为参数提及。

首先，导入所需的库-

import pandas as pd

MultiIndex是Pandas对象的多级或分层索引对象。创建数组-

arrays = [[2, 4, 3, 1], [Peter, Chris, Andy, Jacob], [50, 30, 40, 70]]

“names”参数设置每个索引级别的名称。将from_arrays()被用来创建一个多指标-

multiIndex = pd.MultiIndex.from_arrays(arrays, names=(rank, student, points))

使用交换MultiIndex的级别swaplevel()。第一个参数是要交换的第一级索引。第二个参数是要交换的第二级索引-

print("\nSwap levels in MultiIndex...\n",multiIndex.swaplevel(0,2))

示例

以下是代码-

import pandas as pd #MultiIndexisamulti-level,orhierarchical,indexobjectforpandasobjects #Createarrays arrays = [[2, 4, 3, 1], [Peter, Chris, Andy, Jacob], [50, 30, 40, 70]] # The "names" parameter sets the names for each of the index levels #Thefrom_arrays()isusedtocreateaMultiIndex multiIndex = pd.MultiIndex.from_arrays(arrays, names=(rank, student, points)) #displaytheMultiIndex print("The MultiIndex...\n",multiIndex) #getthelevelsinMultiIndex print("\nThe levels in MultiIndex...\n",multiIndex.levels) #swaplevelsofMultiIndexusingswaplevel() #The1stparameteristhefirstlevelofindextobeswapped #The2ndparameteristhesecondlevelofindextobeswapped print("\nSwap levels in MultiIndex...\n",multiIndex.swaplevel(0,2))输出结果

这将产生以下输出-

The MultiIndex... MultiIndex([(2, Peter, 50), (4, Chris, 30), (3, Andy, 40), (1, Jacob, 70)], names=[rank, student, points]) The levels in MultiIndex... [[1, 2, 3, 4], [Andy, Chris, Jacob, Peter], [30, 40, 50, 70]] Swap levels in MultiIndex... MultiIndex([(50, Peter, 2), (30, Chris, 4), (40, Andy, 3), (70, Jacob, 1)], names=[points, student, rank])