Python Collections Module

The collections module in Python provides alternatives to the general-purpose built-in containers like dict, list, set, and tuple. It includes useful data types such as Counter, defaultdict, OrderedDict, namedtuple, deque, and more.

Commonly Used Data Types

• Counter: A dictionary subclass used to count the occurrences of elements in an iterable.
• defaultdict: A dictionary subclass that provides a default value for missing keys.
• OrderedDict: A dictionary subclass that maintains the order of elements as they were added.
• namedtuple: A subclass of tuple with named fields, making tuples more readable.
• deque: A double-ended queue that allows for efficient appends and pops from both ends.

from collections import Counter
# Example: Counting occurrences of elements in a list
numbers = [1, 2, 2, 3, 3, 3, 4, 4, 4, 4]
count = Counter(numbers)
print(count)  # Output: Counter({4: 4, 3: 3, 2: 2, 1: 1})
            

from collections import defaultdict
# Example: Using defaultdict to handle missing keys
my_dict = defaultdict(int)
my_dict['apple'] += 1
my_dict['banana'] += 2
print(my_dict)  # Output: defaultdict(, {'apple': 1, 'banana': 2})
            

from collections import namedtuple
# Example: Creating and using namedtuple
Person = namedtuple('Person', ['name', 'age'])
p = Person(name='Alice', age=30)
print(p.name, p.age)  # Output: Alice 30
            

The collections module provides efficient and specialized container data types that can help make your code more readable and performant.