How do I use defaultdict from the collections module in Python?

Can you explain how to use defaultdict from the collections module in Python?

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

How do I initialize a defaultdict with a default value?

You can initialize it by passing a function that returns the default value. For example: defaultdict(int) will create a defaultdict where each key's default value is 0.

Can you give me an example of how to use it in a program?

Absolutely! Here's a simple example:

from collections import defaultdict

word_count = defaultdict(int)

for word in ['apple', 'banana', 'apple']:
    word_count[word] += 1

print(word_count)

This will output: defaultdict(<class 'int'>, {'apple': 2, 'banana': 1})

What are some common use cases for defaultdict?

Common use cases include counting items, grouping data, and creating nested dictionaries without needing to check for key existence.