Python Pandas - 删除指定级别的 MultiIndex 并返回

要删除指定级别的 MultiIndex 并返回，在 Pandas 中使用 **MultiIndex.droplevel()** 方法。将要删除的级别作为参数设置。

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。from_arrays() 用于创建 MultiIndex -

multiIndex = pd.MultiIndex.from_arrays(arrays, names=('ranks', 'student'))

删除特定级别。级别 1 即第 1 级已删除” -

print("\nMulti-index after dropping a level...\n",multiIndex.droplevel(1))

示例

代码如下 -

import pandas as pd

# MultiIndex is a multi-level, or hierarchical, index object for pandas objects
# Create arrays
arrays = [[2, 4, 3, 1], ['Peter', 'Chris', 'Andy', 'Jacob']]

# The "names" parameter sets the names for each of the index levels
# The from_arrays() is used to create a MultiIndex
multiIndex = pd.MultiIndex.from_arrays(arrays, names=('ranks', 'student'))

# display the MultiIndex
print("The Multi-index...\n",multiIndex)

# get the levels in MultiIndex
print("\nThe levels in Multi-index...\n",multiIndex.levels)

# Drop a specific level
# The level is 1 i.e. level 1 gets dropped
print("\nMulti-index after dropping a level...\n",multiIndex.droplevel(1))

输出

将生成以下输出 -

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']]

Multi-index after dropping a level...
   Int64Index([2, 4, 3, 1], dtype='int64', name='ranks')

AmitDiwan

更新于: 2021-10-19

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