Pandas: How to make a deep copy of a Series

Updated: February 17, 2024 By: Guest Contributor Post a comment

Introduction

Pandas, an open-source library, provides high-performance, easy-to-use data structures, and data analysis tools for the Python programming language. Among its core data structures are the Series and DataFrame, which are essential for data analysis and manipulation tasks. This tutorial will focus on a Series – a one-dimensional array-like object capable of holding any data type. We’ll explore how to make a deep copy of a Series in Pandas, ensuring that the data manipulation performed on the copied Series does not affect the original one.

Understanding Deep Copy in Pandas

First, let’s understand what we mean by a deep copy. A deep copy creates a new object and recursively adds the copies of nested objects present in the original object. This means that if you modify the new (deep copied) object, it will not affect the original object. In contrast, a shallow copy does not create copies of nested objects but instead creates a reference to the original objects. Therefore, changes in the shallow copy may reflect in the original object, which is not desirable when you want to manipulate data without altering the original data.

Basic Deep Copy Example

import pandas as pd

# Creating a Series
original_series = pd.Series([1, 2, 3, 4, 5])

# Making a deep copy
deep_copied_series = original_series.copy(deep=True)

# Modifying the deep copied Series
deep_copied_series[0] = 10

print("Original Series:", original_series)
print("Deep Copied Series:", deep_copied_series)

This example demonstrates that modifying the deep copied Series does not affect the original Series. Here, changing the first element of the deep copied Series to 10 did not reflect in the original Series, indicating a successful deep copy.

Ensuring Indexed Data Integrity

Deep copying is not just about the data elements but also about maintaining the structure and indexing of the Series. It’s crucial when working with data aligned with specific indices. Let’s look at an advanced example.

import pandas as pd

# Creating a Series with index
original_series = pd.Series([10, 20, 30, 40, 50], index=['a', 'b', 'c', 'd', 'e'])

# Making a deep copy with index
deep_copied_series = original_series.copy(deep=True)

# Modifying the index of the deep copied Series
deep_copied_series.index = ['A', 'B', 'C', 'D', 'E']

print("Original Series:\n", original_series)
print("Deep Copied Series:\n", deep_copied_series)

This example highlights that changing the index of the deep copied Series did not affect the index of the original Series, thus preserving the integrity of indexed data.

Working with Complex Data

Series in Pandas can hold more complex data structures, such as dictionaries or even other Series. Deep copying becomes increasingly significant when dealing with such data. The following example shows deep copying a Series containing dictionaries.

import pandas as pd

# Creating a Series with dictionaries as data
original_series = pd.Series([{\"a\": 1, \"b\": 2}, {\"c\": 3, \"d\": 4}])

# Making a deep copy
deep_copied_series = original_series.copy(deep=True)

# Modifying a value in the deep copied Series' dictionary
deep_copied_series[0]['a'] = 10

print("Original Series:\n", original_series)
print("Deep Copied Series:\n", deep_copied_series)

In this advanced example, changing a value within a dictionary in the deep copied Series does not alter the respective value in the original Series’ dictionary, thus emphasizing the essence of deep copying.

Conclusion

This tutorial explored several aspects of making a deep copy of a Series in Pandas, from basic to more advanced examples. We saw that making a deep copy is essential for data manipulation tasks where the integrity of the original data is to be preserved. Whether you are working with simple or complex data structures within a Series, understanding and utilizing the deep copy functionality in Pandas ensures that your data manipulation operations are safe and do not inadvertently alter your original dataset. Embrace the power of deep copying to maintain the sanctity of your data analysis projects.