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Python Pandas DataFrame.loc[] 函数根据传递的输入来定位 DataFrame 的值。

pandas.DataFrame.loc[] 语法

DataFrame.loc[]

参数

这个函数不接受任何参数。然而，它有几种输入方法。你可以阅读它这里。

返回

它返回所需的值。

示例代码：DataFrame.loc[] 定位特定行的方法

import pandas as pd

dataframe=pd.DataFrame({'Attendance': {0: 60, 1: 100, 2: 80,3: 78,4: 95},
                        'Name': {0: 'Olivia', 1: 'John', 2: 'Laura',3: 'Ben',4: 'Kevin'},
                        'Obtained Marks': {0: 90, 1: 75, 2: 82, 3: 64, 4: 45}})

print("The Original Data frame is: \n")
print(dataframe)

dataframe1 = dataframe.loc[0]
print("The Row Data is: \n")
print(dataframe1)

输出：

The Original Data frame is: 

   Attendance    Name  Obtained Marks
0          60  Olivia              90
1         100    John              75
2          80   Laura              82
3          78     Ben              64
4          95   Kevin              45
The Row Data is: 

Attendance            60
Name              Olivia
Obtained Marks        90
Name: 0, dtype: object

函数返回了 0 行的数据。

示例代码：DataFrame.loc[] 定位多行的方法

import pandas as pd

dataframe=pd.DataFrame({'Attendance': {0: 60, 1: 100, 2: 80,3: 78,4: 95},
                        'Name': {0: 'Olivia', 1: 'John', 2: 'Laura',3: 'Ben',4: 'Kevin'},
                        'Obtained Marks': {0: 90, 1: 75, 2: 82, 3: 64, 4: 45}})

print("The Original Data frame is: \n")
print(dataframe)

dataframe1 = dataframe.loc[[0, 1, 2]]
print("The Rows are: \n")
print(dataframe1)

输出：

The Original Data frame is: 

   Attendance    Name  Obtained Marks
0          60  Olivia              90
1         100    John              75
2          80   Laura              82
3          78     Ben              64
4          95   Kevin              45
The Rows are: 

   Attendance    Name  Obtained Marks
0          60  Olivia              90
1         100    John              75
2          80   Laura              82

现在它已经返回了 DataFrame 的多行数据。

示例代码：DataFrame.loc[] 方法来定位特定行和列的数据

import pandas as pd

dataframe=pd.DataFrame({'Attendance': {0: 60, 1: 100, 2: 80,3: 78,4: 95},
                        'Name': {0: 'Olivia', 1: 'John', 2: 'Laura',3: 'Ben',4: 'Kevin'},
                        'Obtained Marks': {0: 90, 1: 75, 2: 82, 3: 64, 4: 45}})

print("The Original Data frame is: \n")
print(dataframe)

dataframe1 = dataframe.loc[0, 'Attendance']
print("The Value is: \n")
print(dataframe1)

输出：

The Original Data frame is: 

   Attendance    Name  Obtained Marks
0          60  Olivia              90
1         100    John              75
2          80   Laura              82
3          78     Ben              64
4          95   Kevin              45
The Value is: 

60

函数返回索引 0 处的 Attendance 值。