which of the following matches keys to values and stores and stored them
efficeinct
simple data
structure array
hash table
The data structure that matches keys to values and stores and retrieves them efficiently is a hash table.
The data structure that matches keys to values and efficiently stores and retrieves them is a hash table.
The data structure that matches keys to values and efficiently stores and retrieves them is a hash table.
To understand how a hash table works, we need to know the key concepts involved.
A hash table consists of an array (simple data structure) in which the keys are stored based on their hashed values. When a value is inserted into a hash table, it is associated with a key. The hash function takes this key as an input and converts it into a unique integer value, called a hash code. This hash code is used as an index in the array to store the key-value pair.
Here is a step-by-step explanation of how a hash table stores and retrieves values:
1. Insertion:
- A key and its associated value are passed to the hash function.
- The hash function calculates the hash code for the key.
- The hash code is used as an index to store the key-value pair in the array.
- If there is already a value stored at that index, a collision occurs.
- Resolving collisions can be done using various techniques like chaining or open addressing.
2. Retrieval:
- To retrieve a value based on a key, the hash function is again applied to the key to obtain the hash code.
- The hash code is used as an index to search for the key-value pair in the array.
- If a value is found at that index, it is returned.
- In case of collisions, additional steps might be needed to find the correct key-value pair, depending on the collision resolution method used.
A hash table provides efficient insertion, lookup, and deletion operations for storing and retrieving key-value pairs. It is widely used in applications where fast access to data based on a unique identifier (key) is necessary, such as databases, caches, and language implementations.
In summary, a hash table is a data structure that matches keys to values and stores them efficiently using a hash function and an array.