Python Built-in Dictionary
In Python, the built-in dictionary is a mutable, unordered collection of key-value pairs. It is implemented as a hash table, providing fast lookups, insertions, and deletions. Dictionaries are created using curly braces `{}` or the `dict()` constructor, where each key-value pair is separated by a colon `:`. Keys in a dictionary must be unique and immutable (such as strings, numbers, or tuples), while values can be of any data type, including other dictionaries. Common operations on dictionaries include accessing values by key, adding or updating key-value pairs, deleting key-value pairs, iterating over keys, values, or items, and checking membership. Python dictionaries are widely used for mapping and associating keys with values, making them essential for tasks like caching, data manipulation, configuration settings, and implementing associative arrays or hash tables.