Python Pandas - 如何对多索引进行排序
要创建MultiIndex,请使用from_arrays()方法。但是,要对MultiIndex进行排序,请使用.Pandas中的方法。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], ['John', 'Tim', 'Jacob', 'Chris']]
“names”参数设置每个索引级别的名称。将from_arrays()用于创建一个MultiInde-
multiIndex = pd.MultiIndex.from_arrays(arrays, names=('ranks', 'student'))
排序多索引。默认排序在级别0-
print("\nSort MultiIndex...\n",multiIndex.sortlevel())
示例
以下是代码-
import pandas as pd #MultiIndexisamulti-level,orhierarchical,indexobjectforpandasobjects #Createarrays arrays = [[2, 4, 3, 1], ['John', 'Tim', 'Jacob', 'Chris']] # 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 #Thedefaultsortsatlevel0 print("\nSort MultiIndex...\n",multiIndex.sortlevel())输出结果
这将产生以下输出-
The Multi-index... MultiIndex([(2, 'John'), (4, 'Tim'), (3, 'Jacob'), (1, 'Chris')], names=['ranks', 'student']) The levels in Multi-index... [[1, 2, 3, 4], ['Chris', 'Jacob', 'John', 'Tim']] Sort MultiIndex... (MultiIndex([(1, 'Chris'), (2, 'John'), (3, 'Jacob'), (4, 'Tim')], names=['ranks', 'student']), array([3, 0, 2, 1], dtype=int64))