What are some advanced features of Python dictionaries?

What are some advanced features of Python dictionaries?

Python dictionaries have several advanced features, such as dictionary comprehensions, merging dictionaries, and using default values with defaultdict.

Can you explain dictionary comprehensions with an example?

Sure! A dictionary comprehension allows you to create a dictionary in a single line. For example: squared = {x: x**2 for x in range(5)} creates a dictionary with numbers as keys and their squares as values.

What about merging dictionaries? How can I do that?

You can merge dictionaries using the update() method or the | operator in Python 3.9 and later. For example: dict1 | dict2 merges dict1 and dict2.

What is defaultdict and how is it different from a regular dictionary?

defaultdict is a subclass of the built-in dict that provides a default value for a nonexistent key. For example, from collections import defaultdict; d = defaultdict(int) initializes missing keys with 0.