How do I copy dicts in Python safely and idiomatically?

In Python, copying dictionaries can be done in a few different ways, but it's important to do it safely to avoid unintentional side effects. Here are some common methods for copying dictionaries idiomatically:

  • Using the `copy()` method: This creates a shallow copy of the dictionary.
  • Using the `dict()` constructor: This also creates a shallow copy.
  • Using dictionary comprehension: This is useful for transforming the keys and values while copying.
  • Using the `copy` module: This provides a `deepcopy()` function for deep copies if nested dictionaries are involved.

Here's how you can copy a dictionary safely:

# Example of copying a dictionary safely in Python original_dict = {'a': 1, 'b': {'c': 2}} # Shallow copy using copy() method shallow_copy = original_dict.copy() # Shallow copy using dict() constructor another_shallow_copy = dict(original_dict) # Deep copy using copy module import copy deep_copy = copy.deepcopy(original_dict)

Python copy dictionary shallow copy deep copy idiomatic Python

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