The collections module in Python provides a variety of specialized container data types that are useful for different purposes. Here are some additional methods and functionality of the collections module along with examples:
1. namedtuple Factory Function:
collections.namedtuple(typename, field_names, [verbose=False, rename=False]): Creates a new named tuple subclass with named fields.
from collections import namedtuple
Point = namedtuple("Point", ["x", "y"])
p = Point(1, 2)
print("Point:", p)2. deque (Double-Ended Queue):
collections.deque([iterable[, maxlen]]): Creates a new deque object.
Provides efficient O(1) operations for adding and removing elements from both ends.
from collections import deque
d = deque([1, 2, 3])
d.append(4)
d.appendleft(0)
print("Deque:", d)3. Counter (Counting Elements):
collections.Counter([iterable-or-mapping]): Creates a dictionary-like object for counting elements.
from collections import Counter
colors = ['red', 'blue', 'red', 'green', 'blue', 'red']
color_count = Counter(colors)
print("Color Count:", color_count)4. defaultdict (Default Values):
collections.defaultdict([default_factory[, ...]]): Creates a dictionary with default values for missing keys.
from collections import defaultdict
d = defaultdict(int)
d['a'] += 1
print("Default Dict:", d['a'])5. OrderedDict (Ordered Dictionary):
collections.OrderedDict([items]): Creates a dictionary that maintains the order of insertion.
from collections import OrderedDict
d = OrderedDict()
d['one'] = 1
d['two'] = 2
print("Ordered Dict:", d)6. ChainMap (Combining Dictionaries):
collections.ChainMap(*maps): Combines multiple dictionaries into a single view.
from collections import ChainMap
dict1 = {'a': 1, 'b': 2}
dict2 = {'b': 3, 'c': 4}
combined_dict = ChainMap(dict1, dict2)
print("Combined Dict:", combined_dict['b'])7. UserDict, UserList, and UserString:
These classes provide user-friendly wrapper classes for dictionaries, lists, and strings, respectively.
from collections import UserDict, UserList, UserString
class MyDict(UserDict):
pass
d = MyDict({"a": 1, "b": 2})
print("User Dictionary:", d)These are some additional methods and functionality provided by the collections module in Python. They are valuable for solving various programming tasks efficiently using specialized data structures.