How to copy an object in Python

In Python, you can create a copy of an object using the copy module. There are two main types of copies: shallow copy and deep copy. These types determine how nested objects within the copied object are handled.

Here's how you can create copies of objects:

Shallow Copy

A shallow copy creates a new object that is a copy of the original object. However, the new object contains references to the same objects that the original object contains. In other words, it copies the top-level structure, but the nested objects are not duplicated.

To create a shallow copy, you can use the copy() method or the copy.copy() function from the copy module.

import copy original_list = [1, [2, 3]] shallow_copied_list = copy.copy(original_list) shallow_copied_list[1][0] = 99 print(original_list) # Output: [1, [99, 3]]

In this example, although the list is copied, the nested list is still shared between the original and the copied list.

Deep Copy

A deep copy creates a new object that is a copy of the original object, including all the nested objects. It recursively creates new objects for all the objects contained within the original object.

To create a deep copy, you can use the copy.deepcopy() function from the copy module.

import copy original_list = [1, [2, 3]] deep_copied_list = copy.deepcopy(original_list) deep_copied_list[1][0] = 99 print(original_list) # Output: [1, [2, 3]]

In this example, the deep copy ensures that the nested list is also copied, so modifying the copied nested list doesn't affect the original list.

Choosing between shallow and deep copies depends on your specific use case. If your object contains nested mutable objects (like lists), a deep copy might be necessary to ensure complete independence. If the object structure is simple and you want to save memory and copying time, a shallow copy might be sufficient.

Keep in mind that the copy module might not work as expected with user-defined classes unless you define the appropriate methods for copying.

Conclusion

Creating copies of objects in Python can be achieved using shallow or deep copies, depending on whether you want to duplicate only the top-level structure or create new copies of nested objects as well.






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