I’ve worked with Python for years, and the simplest way to handle this is by using pop to remove the old key and immediately assign its value to the new key. Here’s an example that works for both regular dictionaries and OrderedDicts while ensuring order is preserved in the latter:
my_dict = {'old_key': 'value'}
my_dict['new_key'] = my_dict.pop('old_key')
print(my_dict)
# Output: {'new_key': 'value'}
This avoids unnecessary iterations. It’s clean, direct, and does the job efficiently.