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Modules in Python: defaultdict

Explore how to use Python's defaultdict from the collections module to handle missing keys automatically. Understand different default_factory options like int, list, or lambda to simplify counting and grouping tasks while avoiding KeyErrors.

Overview of defaultdict

The collections module has a handy tool called defaultdict. The defaultdict is a subclass of Python’s dict that accepts a default_factory as its primary argument. The default_factory is usually a Python type, such as int or list, but we can also use a function or a lambda.

Simple example of counting the occurrence of words

Let’s start by creating a regular Python dictionary ...