Hashing Questions Medium
A hash table and a dictionary are both data structures used for efficient storage and retrieval of key-value pairs. However, there are some differences between the two:
1. Implementation: A hash table is typically implemented as an array of linked lists or as a dynamic array, where each element in the array is called a bucket. On the other hand, a dictionary is a more abstract concept and can be implemented using various data structures, including hash tables.
2. Key types: In a hash table, the keys are usually restricted to be of a specific type, such as integers or strings, and they are hashed to determine the index in the array where the value is stored. In a dictionary, the keys can be of any hashable type, which means they must have a hash function defined and support equality comparison.
3. Collision handling: Hash tables handle collisions that occur when two different keys hash to the same index by using techniques like chaining (using linked lists to store multiple values in the same bucket) or open addressing (finding an alternative empty bucket to store the value). Dictionaries may also handle collisions, but the specific method depends on the chosen implementation.
4. Operations: Both hash tables and dictionaries support common operations like insertion, deletion, and retrieval of key-value pairs. However, the specific syntax and methods used to perform these operations may vary depending on the programming language or library being used.
Overall, the main difference between a hash table and a dictionary lies in their implementation details and the flexibility of key types they support. While a hash table is a specific data structure with a fixed implementation, a dictionary is a more general concept that can be implemented using various data structures, including hash tables.