Mapping Data Types In Python.pptx

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1. Mapping Data Types In Python SlideMake.com

2. Introduction to Mapping Data Types in Python Mapping data types in Python allow us to store data in key-value pairs. The most common mapping data type in Python is the dictionary. Mapping data types are mutable, meaning their values can be changed.

3. Working with Dictionaries Dictionaries are created using curly braces {} or the dict() constructor. Keys in a dictionary must be unique and immutable, such as strings or numbers. Values in a dictionary can be of any data type and can be accessed using their corresponding keys.

4. Basic Operations with Dictionaries Accessing values in a dictionary is done by using the key inside square brackets []. We can add new key-value pairs to a dictionary by assigning a value to a new key. To remove a key-value pair from a dictionary, we can use the del keyword followed by the key.

5. Common Methods for Dictionaries The len() function returns the number of key-value pairs in a dictionary. The keys() method returns a list of all keys in the dictionary. The values() method returns a list of all values in the dictionary.

6. Dictionary Comprehension Dictionary comprehension allows us to create dictionaries in a concise way. We can use a loop to iterate over a sequence and create key-value pairs. It follows the format {key_expression: value_expression for item in sequence}.

7. Other Mapping Data Types Besides dictionaries, Python also provides other mapping data types like OrderedDict and Counter. OrderedDict is a dictionary subclass that remembers the order in which key-value pairs were added. Counter is a dictionary subclass that counts the number of occurrences of each element in a sequence.

8. Immutable Mapping Data Types In addition to mutable mapping data types, Python also offers immutable ones like frozenset. A frozenset is an immutable version of the set data type and can be used as a key in a dictionary. Immutable mapping data types are useful when we need to ensure that the keys won't change.

9. Summary Mapping data types in Python store data in key-value pairs and are mutable. Dictionaries are the most common mapping data type and support various operations and methods. Other mapping data types like OrderedDict and Counter provide additional functionality.

10. References Python Documentation: Mapping Types dict. Available at: https://docs.python.org/3/library/stdtypes.html#dict. Python Documentation: Dictionary Comprehension. Available at: https://docs.python.org/3/tutorial/datastructures.html#dictionaries.