What are the methods of OrderedDict in Python's collections module?

What are the methods of OrderedDict in Python's collections module?

The OrderedDict class in Python's collections module has several methods, including:

1. __init__: Initializes the OrderedDict.
2. __getitem__: Retrieves an item by key.
3. __setitem__: Sets an item by key.
4. move_to_end: Moves an existing key to the end of the OrderedDict.
5. popitem: Removes and returns a (key, value) pair from the OrderedDict.

Can you explain how the move_to_end method works?

Sure! The move_to_end(key, last=True) method moves an existing key to the end of the OrderedDict. If last is True, it moves the key to the end; if False, it moves it to the beginning.

What happens if the key doesn't exist when using move_to_end?

If the key does not exist, move_to_end will raise a KeyError. It's important to ensure the key is present before calling this method.

Are there any performance considerations when using OrderedDict?

Yes, while OrderedDict maintains the order of keys, it may have slightly higher memory overhead and slower performance for certain operations compared to regular dictionaries, especially in older Python versions.