What is the usage of defaultdict in Python's collections module?

What is the usage of defaultdict in Python's collections module?

The defaultdict is a subclass of the built-in dict class. It overrides one method to provide a default value for a nonexistent key.

Can you give me an example of how to use defaultdict?

Sure! Here's a simple example:

from collections import defaultdict

default_dict = defaultdict(int)

default_dict['a'] += 1
print(default_dict)

This will output {'a': 1}.

What happens if I try to access a key that doesn't exist?

If you access a key that doesn't exist, defaultdict will automatically create it with the default value you specified, like 0 for int.

Are there other default types I can use with defaultdict?

Yes, you can use any callable as a default factory, such as list, set, or even a custom function.