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

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

The defaultdict is a subclass of the built-in dict class. It provides a default value for the key that does not exist, which can improve performance in certain scenarios by avoiding key errors.

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

Sure! Here's a simple example:

from collections import defaultdict

# Create a defaultdict with int as the default factory
my_dict = defaultdict(int)

# Incrementing values
my_dict['a'] += 1
my_dict['b'] += 2

print(my_dict)  # Output: defaultdict(<class 'int'>, {'a': 1, 'b': 2})

How does defaultdict compare to a regular dictionary in terms of speed?

In general, defaultdict can be faster than a regular dictionary when you frequently access keys that may not exist, as it avoids the overhead of checking for key existence and raising a KeyError.

Are there any downsides to using defaultdict?

Yes, one downside is that it can lead to unexpected behavior if you're not careful, as it automatically creates keys with default values. This can result in larger memory usage if many default keys are created unintentionally.