Get last n records of a Pandas DataFrame

When working with large datasets in Pandas, you often need to examine the most recent entries. The tail() method provides an efficient way to retrieve the last n records from a DataFrame.

Syntax

DataFrame.tail(n=5)

Parameters:

• n Number of rows to return from the end (default is 5)

Creating a Sample DataFrame

Let's create a DataFrame to demonstrate the tail() method ?

import pandas as pd

data = {'Name': ['John', 'Mark', 'Alice', 'Julie', 'Lisa', 'David'],
        'Age': [23, 34, 45, 19, 28, 31],
        'Gender': ['M', 'M', 'F', 'F', 'F', 'M']}

df = pd.DataFrame(data)
print("Original DataFrame:")
print(df)

Original DataFrame:
    Name  Age Gender
0   John   23      M
1   Mark   34      M
2  Alice   45      F
3  Julie   19      F
4   Lisa   28      F
5  David   31      M

Getting Last n Records

Get Last 3 Records

import pandas as pd

data = {'Name': ['John', 'Mark', 'Alice', 'Julie', 'Lisa', 'David'],
        'Age': [23, 34, 45, 19, 28, 31],
        'Gender': ['M', 'M', 'F', 'F', 'F', 'M']}

df = pd.DataFrame(data)

last_3_records = df.tail(3)
print("Last 3 records:")
print(last_3_records)

Last 3 records:
    Name  Age Gender
3  Julie   19      F
4   Lisa   28      F
5  David   31      M

Reset Index (Optional)

You can reset the index to start from 0 using reset_index() ?

import pandas as pd

data = {'Name': ['John', 'Mark', 'Alice', 'Julie', 'Lisa', 'David'],
        'Age': [23, 34, 45, 19, 28, 31],
        'Gender': ['M', 'M', 'F', 'F', 'F', 'M']}

df = pd.DataFrame(data)

last_3_records = df.tail(3).reset_index(drop=True)
print("Last 3 records with reset index:")
print(last_3_records)

Last 3 records with reset index:
    Name  Age Gender
0  Julie   19      F
1   Lisa   28      F
2  David   31      M

Different Values of n

import pandas as pd

data = {'Name': ['John', 'Mark', 'Alice', 'Julie', 'Lisa', 'David'],
        'Age': [23, 34, 45, 19, 28, 31],
        'Gender': ['M', 'M', 'F', 'F', 'F', 'M']}

df = pd.DataFrame(data)

print("Last 1 record:")
print(df.tail(1))
print("\nLast 2 records:")
print(df.tail(2))
print("\nDefault (last 5 records):")
print(df.tail())

Last 1 record:
    Name  Age Gender
5  David   31      M

Last 2 records:
    Name  Age Gender
4   Lisa   28      F
5  David   31      M

Default (last 5 records):
    Name  Age Gender
1   Mark   34      M
2  Alice   45      F
3  Julie   19      F
4   Lisa   28      F
5  David   31      M

Common Use Cases

• Data Validation Check recent data entries after insertion

• Time Series Analysis Examine the latest observations

• Model Training Use recent data for machine learning models

• Data Monitoring Monitor the most recent records in streaming data

Conclusion

The tail() method provides a simple and efficient way to retrieve the last n records from a Pandas DataFrame. Use reset_index(drop=True) when you need the resulting DataFrame to have a continuous index starting from 0.