Quick data inspection
Inspect the final records of a loaded or transformed table.
Pandas · Module
df.tail
Returns the last rows of a DataFrame by positional order. It selects five rows by default and supports positive or negative values of n.
How it works
Call DataFrame.tail to obtain rows from the end of a DataFrame by positional order. The default selects five rows; a positive integer selects that many, while a negative integer omits that many rows from the beginning.
Syntax
DataFrame.tail(*n=5*)Parameters
| Name | Type | Description |
|---|---|---|
n | int, default 5 | Number of rows to select. |
Returns
The last n rows of the caller object.
Key points
- The method selects rows at the end of the DataFrame.
- Selection is positional, so the method examines row order rather than filtering by column values.
- Use it as a compact inspection step after transformations that may change row order or contents.
nis an integer and defaults to five when omitted.- For a nonnegative value,
ncontrols the number of rows returned.
Common mistakes
- A negative value does not mean “take the last |n| rows”; it excludes that many rows from the front.
- Requesting more rows than exist returns the complete DataFrame rather than raising an error.
Example: Select the final rows
import pandas as pd
df = pd.DataFrame({"animal": ["alligator", "bee", "falcon", "lion", "monkey"]})
print(df.tail(2))
Prints the final two rows of the DataFrame.
When to use it
Verify sorted output
Confirm the resulting order after sorting.
Inspect appended rows
Check newly appended records at the end of a table.
Interview questions
QWhat does DataFrame.tail return?
It returns the final n rows according to positional order. With no argument, n defaults to 5.
Follow-up: What does tail(-3) do? It returns every row except the first three, equivalent to positional slicing with df[3:].
QWhat is the n parameter and what happens when it is too large?
The argument is an integer specifying how many rows to select, and its default is 5. The method returns the last n rows of the caller object.
Follow-up: What happens when the requested count exceeds the row count? The method returns all available rows.
QHow does negative n differ from positive n?
A positive n selects rows from the end. A negative n instead removes the first |n| rows, so tail(-3) is equivalent to df[3:].
Follow-up: Why is this useful in practice? It provides a quick positional check after operations such as sorting or appending rows.
Related
DataFrame.head