获取和设置 Pandas DataFrame 索引名
Suraj Joshi
2023年1月30日
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。
作者： Suraj Joshi
Suraj Joshi is a backend software engineer at Matrice.ai.
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