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本教程介绍了如何在 Pandas DataFrame 中设置和获取索引列的名称。我们将在文章中使用下面的 DataFrame 示例。

import pandas as pd

my_df = pd.DataFrame(
    {
        "Applicant": ["Ratan", "Anil", "Mukesh", "Kamal"],
        "Hometown": ["Delhi", "Pune", "Dhangadi", "Kolkata"],
        "Score": [85, 87, 90, 89],
    },
    index=["2021-01-03", "2021-01-04", "2021-01-05", "2021-01-06"],
)

print(my_df)

输出：

           Applicant  Hometown  Score
2021-01-03     Ratan     Delhi     85
2021-01-04      Anil      Pune     87
2021-01-05    Mukesh  Dhangadi     90
2021-01-06     Kamal   Kolkata     89

获取 DataFrame 中索引列的名称

我们可以通过索引列的 name 属性来获取 DataFrame 的索引列的名称。

import pandas as pd

my_df = pd.DataFrame(
    {
        "Applicant": ["Ratan", "Anil", "Mukesh", "Kamal"],
        "Hometown": ["Delhi", "Pune", "Dhangadi", "Kolkata"],
        "Score": [85, 87, 90, 89],
    },
    index=["2021-01-03", "2021-01-04", "2021-01-05", "2021-01-06"],
)

print("The DataFrame is:")
print(my_df, "\n")

print("Name of Index Column of the DataFrame is:")
print(my_df.index.name)

输出：

The DataFrame is:
           Applicant  Hometown  Score
2021-01-03     Ratan     Delhi     85
2021-01-04      Anil      Pune     87
2021-01-05    Mukesh  Dhangadi     90
2021-01-06     Kamal   Kolkata     89

Name of Index Column of the DataFrame is:
None

由于我们没有为 my_df DataFrame 设置索引列的名称，所以得到 my_df DataFrame 的索引列名称为 None。

通过设置 name 属性来设置 DataFrame 的索引列的名称

我们只需设置 DataFrame 的 index 属性的 name 值，就可以设置 DataFrame 的索引列的名称。

import pandas as pd

my_df = pd.DataFrame(
    {
        "Applicant": ["Ratan", "Anil", "Mukesh", "Kamal"],
        "Hometown": ["Delhi", "Pune", "Dhangadi", "Kolkata"],
        "Score": [85, 87, 90, 89],
    },
    index=["2021-01-03", "2021-01-04", "2021-01-05", "2021-01-06"],
)

print("Initial DataFrame:")
print(my_df, "\n")

my_df.index.name = "Date"

print("DataFrame after setting the name of Index Column:")
print(my_df, "\n")

print("Name of Index Column of the DataFrame is:")
print(my_df.index.name)

输出：

Initial DataFrame:
           Applicant  Hometown  Score
2021-01-03     Ratan     Delhi     85
2021-01-04      Anil      Pune     87
2021-01-05    Mukesh  Dhangadi     90
2021-01-06     Kamal   Kolkata     89

DataFrame after setting the name of Index Column:
           Applicant  Hometown  Score
Date
2021-01-03     Ratan     Delhi     85
2021-01-04      Anil      Pune     87
2021-01-05    Mukesh  Dhangadi     90
2021-01-06     Kamal   Kolkata     89

Name of Index Column of the DataFrame is:
Date

它将 my_df 的 index 属性值设置为 Date。

使用 rename_axis() 方法设置 DataFrame 的索引列的名称

我们可以将索引列的名称作为参数传递给 rename_axis() 方法来设置 DataFrame 中索引列的名称。

import pandas as pd

my_df = pd.DataFrame(
    {
        "Applicant": ["Ratan", "Anil", "Mukesh", "Kamal"],
        "Hometown": ["Delhi", "Pune", "Dhangadi", "Kolkata"],
        "Score": [85, 87, 90, 89],
    },
    index=["2021-01-03", "2021-01-04", "2021-01-05", "2021-01-06"],
)

print("Initial DataFrame:")
print(my_df, "\n")

my_df = my_df.rename_axis("Date")

print("DataFrame after setting the name of Index Column:")
print(my_df, "\n")

print("Name of Index Column of the DataFrame is:")
print(my_df.index.name)

输出：

Initial DataFrame:
           Applicant  Hometown  Score
2021-01-03     Ratan     Delhi     85
2021-01-04      Anil      Pune     87
2021-01-05    Mukesh  Dhangadi     90
2021-01-06     Kamal   Kolkata     89

DataFrame after setting the name of Index Column:
           Applicant  Hometown  Score
Date
2021-01-03     Ratan     Delhi     85
2021-01-04      Anil      Pune     87
2021-01-05    Mukesh  Dhangadi     90
2021-01-06     Kamal   Kolkata     89

Name of Index Column of the DataFrame is:
Date

它使用 rename_axis() 方法将 DataFrame my_df 的 index 列名设置为 Date。