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'])