Python Pandas - How to select rows from a DataFrame by passing row label

To select rows by passing a label, use the loc[] accessor in Pandas. You can specify the index label to retrieve specific rows from a DataFrame. The loc[] accessor is label-based and allows you to select data by row and column labels.

Creating a DataFrame with Custom Index Labels

First, let's create a DataFrame with custom index labels ?

import pandas as pd

# Create DataFrame with custom index labels
dataFrame = pd.DataFrame([[10, 15], [20, 25], [30, 35]], 
                        index=['x', 'y', 'z'], 
                        columns=['a', 'b'])

print("DataFrame:")
print(dataFrame)

DataFrame:
    a   b
x  10  15
y  20  25
z  30  35

Selecting a Single Row by Label

Use loc[] with the index label to select a specific row ?

import pandas as pd

dataFrame = pd.DataFrame([[10, 15], [20, 25], [30, 35]], 
                        index=['x', 'y', 'z'], 
                        columns=['a', 'b'])

# Select row with label 'z'
selected_row = dataFrame.loc['z']
print("Selected row 'z':")
print(selected_row)
print("\nData type:", type(selected_row))

Selected row 'z':
a    30
b    35
Name: z, dtype: int64

Data type: <class 'pandas.core.series.Series'>

Selecting Multiple Rows by Labels

You can also select multiple rows by passing a list of labels ?

import pandas as pd

dataFrame = pd.DataFrame([[10, 15], [20, 25], [30, 35]], 
                        index=['x', 'y', 'z'], 
                        columns=['a', 'b'])

# Select multiple rows
selected_rows = dataFrame.loc(['x', 'z'])
print("Selected rows 'x' and 'z':")
print(selected_rows)
print("\nData type:", type(selected_rows))

Selected rows 'x' and 'z':
    a   b
x  10  15
z  30  35

Data type: <class 'pandas.core.frame.DataFrame'>

Key Points

• loc[] uses square brackets, not parentheses like loc()
• Selecting a single row returns a Series
• Selecting multiple rows returns a DataFrame
• Index labels must exist in the DataFrame, otherwise a KeyError is raised

Conclusion

Use dataFrame.loc['label'] to select rows by index labels in Pandas. This method is intuitive and allows both single and multiple row selection using label-based indexing.