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2 days ago · collections — Container datatypes ¶. Source code: Lib/collections/__init__.py. This module implements specialized container datatypes providing alternatives to Python’s general purpose built-in containers, dict, list , set, and tuple. ChainMap objects ¶. Added in version 3.3.
Python’s collections module provides a rich set of specialized container data types carefully designed to approach specific programming problems in a Pythonic and efficient way.
- Counters
- OrderedDict
- Defaultdict
- ChainMap
- Namedtuple
- Deque
- UserDict
- Userlist
- UserString
A counteris a sub-class of the dictionary. It is used to keep the count of the elements in an iterable in the form of an unordered dictionary where the key represents the element in the iterable and value represents the count of that element in the iterable. Note: It is equivalent to bag or multiset of other languages. Syntax:
An OrderedDict is also a sub-class of dictionary but unlike dictionary, it remembers the order in which the keys were inserted. Syntax: Example: Output: While deleting and re-inserting the same key will push the key to the last to maintain the order of insertion of the key. Example: Output: Note: for more information, refer OrderedDict in Python
A DefaultDictis also a sub-class to dictionary. It is used to provide some default values for the key that does not exist and never raises a KeyError. Syntax: default_factory is a function that provides the default value for the dictionary created. If this parameter is absent then the KeyError is raised.
A ChainMapencapsulates many dictionaries into a single unit and returns a list of dictionaries. Syntax: Example: Output:
A NamedTuplereturns a tuple object with names for each position which the ordinary tuples lack. For example, consider a tuple names student where the first element represents fname, second represents lname and the third element represents the DOB. Suppose for calling fname instead of remembering the index position you can actually call the element ...
Deque (Doubly Ended Queue)is the optimized list for quicker append and pop operations from both sides of the container. It provides O(1) time complexity for append and pop operations as compared to list with O(n) time complexity. Syntax: This function takes the list as an argument. Example: Output:
UserDictis a dictionary-like container that acts as a wrapper around the dictionary objects. This container is used when someone wants to create their own dictionary with some modified or new functionality. Syntax: Example: Output: Note: For more information, refer UserDict in Python
UserList is a list like container that acts as a wrapper around the list objects. This is useful when someone wants to create their own list with some modified or additional functionality. Syntax: Example: Output: Note:For more information, refer UserList in Python
UserStringis a string like container and just like UserDict and UserList it acts as a wrapper around string objects. It is used when someone wants to create their own strings with some modified or additional functionality. Syntax: Example: Output: Note:For more information, refer UserString in Python
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Lists are used to store multiple items in a single variable. Lists are one of 4 built-in data types in Python used to store collections of data, the other 3 are Tuple, Set, and Dictionary, all with different qualities and usage. Lists are created using square brackets:
This module implements specialized container datatypes providing alternatives to Python’s general purpose built-in containers, dict, list , set, and tuple. namedtuple() factory function for creating tuple subclasses with named fields. deque. list-like container with fast appends and pops on either end. ChainMap.
Collections is a built-in python module that provides useful container types. They allow us to store and access values in a convenient way. Generally, you would have used lists, tuples, and dictionaries.
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What is collections Python?
What is a collection module in Python?
What is the difference between a dictionary and a collection module?
What are the different types of containers in Python?
The collection module in Python has different containers. A container is an object that holds a number of other objects and provides a way to access the objects contained in them. The container then iterates over the items.
