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

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

You can use defaultdict to provide default values for missing keys in a dictionary. For example, from collections import defaultdict and then d = defaultdict(int) will create a dictionary that defaults to 0 for missing keys.

Can you give me an example of how it works?

Sure! Here's a simple example: d = defaultdict(list) and then d['a'].append(1). If you access d['a'], it will return [1], and if you access d['b'], it will return [] instead of raising a KeyError.

What are some common use cases for defaultdict?

Common use cases include counting items, grouping data, and initializing lists or sets for keys without needing to check if they exist first.

Are there any limitations to using defaultdict?

One limitation is that it can lead to unexpected behavior if you're not careful, as it automatically creates keys that may not be intended. It's important to understand when to use it.