Python Pandas - 如何在特定级别对 MultiIndex 进行排序

要创建MultiIndex，请使用from_arrays()方法。但是，要在特定级别对MultiIndex进行排序，请使用Pandas中的方法。将级别设置为参数。multiIndex.sortlevel()

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]]

“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=(ranks, student))

排序多索引。要排序的特定级别设置为参数，即此处的级别1-

print("\nSort MultiIndex at the requested level...\n",multiIndex.sortlevel(1))

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]] # The "names" parameter sets the names for each of the index levels #Thefrom_arrays()isusedtocreateaMultiIndex multiIndex = pd.MultiIndex.from_arrays(arrays, names=(ranks, student)) #displaytheMultiIndex print("The Multi-index...\n",multiIndex) #getthelevelsinMultiIndex print("\nThe levels in Multi-index...\n",multiIndex.levels) #SortMultiIndex #Thespecificleveltosortissetasaparameteri.e.level1here print("\nSort MultiIndex at the requested level...\n",multiIndex.sortlevel(1))输出结果

这将产生以下输出-

The Multi-index... MultiIndex([(2, Peter), (4, Chris), (3, Andy), (1, Jacob)], names=[ranks, student]) The levels in Multi-index... [[1, 2, 3, 4], [Andy, Chris, Jacob, Peter]] Sort MultiIndex at the requested level... (MultiIndex([(3, Andy), (4, Chris), (1, Jacob), (2, Peter)], names=[ranks, student]), array([2, 1, 3, 0], dtype=int64))