How to Use size in pandas: Syntax and Examples

In pandas, size returns the total number of elements in a DataFrame or Series. For a DataFrame, it equals the number of rows multiplied by columns, and for a Series, it equals the number of elements.

Syntax

The size attribute is used without parentheses because it is a property, not a method. It can be applied to both DataFrame and Series objects.

• DataFrame.size: Returns total elements (rows × columns).
• Series.size: Returns total elements in the series.

python

df.size
series.size

Example

This example shows how to use size on a DataFrame and a Series to get the total number of elements.

python

import pandas as pd

data = {'A': [1, 2, 3], 'B': [4, 5, 6]}
df = pd.DataFrame(data)

print('DataFrame size:', df.size)  # 3 rows * 2 columns = 6

series = pd.Series([10, 20, 30, 40])
print('Series size:', series.size)  # 4 elements

Output

DataFrame size: 6
Series size: 4

Common Pitfalls

A common mistake is confusing size with shape or len(). size gives total elements, while shape gives dimensions and len() gives number of rows for DataFrames.

Also, size is an attribute, so do not use parentheses like df.size().

python

import pandas as pd

df = pd.DataFrame({'X': [1, 2], 'Y': [3, 4]})

# Wrong: calling size as a method
# print(df.size())  # This will raise a TypeError

# Correct usage
print(df.size)  # Outputs 4

# Difference from shape and len
print(df.shape)  # Outputs (2, 2)
print(len(df))   # Outputs 2

Output

4
(2, 2)
2

Quick Reference

Summary of related pandas attributes:

Attribute	Description	Example Output
size	Total number of elements (rows × columns)	6 for 3x2 DataFrame
shape	Tuple of (rows, columns)	(3, 2)
len()	Number of rows in DataFrame or elements in Series	3 for DataFrame, 4 for Series

Key Takeaways

size returns total elements in DataFrame or Series.

size is an attribute, not a method; do not use parentheses.

size differs from shape and len() in what it returns.

Use size to quickly find total data points in your pandas object.