Explain the difference between a shallow copy and a deep copy in Python.

Question

Aryan Kumar · Answer

Sure. In Python, there are two types of copies: shallow copy and deep copy.

Shallow copy: A shallow copy creates a new object that contains the same references as the original object. This means that if you change the value of an element in the shallow copy, the value of the element in the original object will also change.
Deep copy: A deep copy creates a new object that contains the same data as the original object. This means that if you change the value of an element in the deep copy, the value of the element in the original object will not change.

Here is an example of how to create a shallow copy and a deep copy in Python:

Python

list1 = [1, 2, 3]
list2 = list1[:]  # shallow copy
list3 = copy.deepcopy(list1)  # deep copy

list1[0] = 10

print(list1)
print(list2)
print(list3)

This code will print the following output:

Code snippet

[10, 2, 3]
[1, 2, 3]
[1, 2, 3]

As you can see, the shallow copy list2 contains the same references as the original list list1. When we change the value of the first element in list1, the value of the first element in list2 also changes.

The deep copy list3 contains the same data as the original list list1, but it does not contain the same references. When we change the value of the first element in list1, the value of the first element in list3 does not change.

Here is a table that summarizes the differences between shallow copy and deep copy:

Feature	Shallow copy	Deep copy
References	The shallow copy contains the same references as the original object.	The deep copy contains the same data as the original object, but it does not contain the same references.
Changes	If you change the value of an element in the shallow copy, the value of the element in the original object will also change.	If you change the value of an element in the deep copy, the value of the element in the original object will not change.
Speed	Shallow copy is faster than deep copy.	Deep copy is slower than shallow copy.

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Explain the difference between a shallow copy and a deep copy in Python.

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