What is the difference between a deep copy and a shallow copy of an object in Python?
Alex K

In Python, when dealing with objects and data structures, it's important to understand the concepts of shallow copy and deep copy, as they determine how objects and their contents are copied. Let's delve into the differences between these two approaches: Shallow Copy: - Definition: A shallow copy creates a new object that references the original object's memory address. However, it doesn't create copies of the object's internal elements. Instead, it copies references to the original elements. As a result, changes made to the original elements may also affect the copied object, and vice versa. - Behavior: With a shallow copy, the top-level object is copied, but the nested objects are shared between the original and copied objects. - Copying Method: Shallow copy can be achieved using thecopy() method from thecopy module or by using the slicing syntax[:] on the original object.

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import copy

original_list = [1, 2, [3, 4]]
shallow_copy = copy.copy(original_list)

original_list[0] = 5
original_list[2][0] = 6

print(original_list)    # Output: [5, 2, [6, 4]]
print(shallow_copy)# Output: [1, 2, [6, 4]]

In this example, thecopy.copy() method creates a shallow copy of theoriginal_list. Modifying the original list's first element (original_list[0] = 5) affects only the original list, but modifying the nested list's first element (original_list[2][0] = 6) affects both the original list and the shallow copy. Deep Copy: - Definition: A deep copy creates a completely independent copy of an object, including all of its internal elements. It doesn't reference the original object's memory address or any of its contents. Consequently, changes made to the original object or its elements won't affect the deep copy, and vice versa. - Behavior: With a deep copy, both the top-level object and all its nested objects are duplicated in memory, resulting in completely separate objects. - Copying Method: Deep copy can be achieved using thecopy.deepcopy() method from thecopy module.

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import copy

original_list = [1, 2, [3, 4]]
deep_copy = copy.deepcopy(original_list)

original_list[0] = 5
original_list[2][0] = 6

print(original_list)    # Output: [5, 2, [6, 4]]
print(deep_copy)   # Output: [1, 2, [3, 4]]

In this example, thecopy.deepcopy() method creates a deep copy of theoriginal_list. Modifying either the original list or the nested list won't affect the other. Summary: In summary, the main difference between a shallow copy and a deep copy in Python lies in how the copying process is performed: - Shallow copy creates a new object that references the memory address of the original object, resulting in shared references to nested objects. - Deep copy creates a new object with completely independent copies of the original object and all its nested objects, ensuring that modifications to one won't affect the other. Understanding these distinctions is crucial for maintaining data integrity and ensuring the desired behavior when working with objects and their copies in Python.

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