PythonAdvanced

Collections Module

Python collections module: Counter, defaultdict, namedtuple, and deque for powerful and efficient data structures.

01Counter for tallies

main.py

from collections import Counter
words = ["a", "b", "a", "c", "a", "b"]
print(Counter(words))

Output

Counter({'a': 3, 'b': 2, 'c': 1})

main.py

from collections import defaultdict
d = defaultdict(int)
for char in "hello":
    d[char] += 1
print(dict(d))

Output

{'h': 1, 'e': 1, 'l': 2, 'o': 1}

main.py

from collections import namedtuple
Point = namedtuple("Point", ["x", "y"])
p = Point(3, 4)
print(p.x, p.y)

Output

3 4

main.py

from collections import deque
q = deque([1, 2, 3])
q.appendleft(0)
q.append(4)
print(list(q))

Output

[0, 1, 2, 3, 4]

main.py

from collections import Counter
print(Counter("mississippi").most_common(2))

Output

[('i', 4), ('s', 4)]