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Search in Hash Table

Search in Hash Table​

The search operation involves retrieving the value associated with a key in a hash table. Hashing ensures efficient lookups based on the key.

  1. Hash the Key: Use the hash function to determine the index.
  2. Check for Key: If the key exists at the computed index, return the corresponding value.
  3. Handle Collision: Properly handle cases where multiple keys map to the same index.

Time Complexity​

  • Average Case: O(1)O(1)
  • Worst Case: O(n)O(n)

Example Code (Python)​

class HashTable:
    def __init__(self):
        self.table = {}

    def search(self, key):
        return self.table.get(key, None)

# Example usage
hash_table = HashTable()
hash_table.table = {'apple': 10, 'banana': 20}
print(hash_table.search('apple'))  # Output: 10

Example Code (JavaScript)​

class HashTable {
    constructor() {
        this.table = {};
    }

    // Method to search for a key in the hash table
    search(key) {
        return this.table.hasOwnProperty(key) ? this.table[key] : null;
    }
}

// Example usage
const hashTable = new HashTable();
hashTable.table = { apple: 10, banana: 20 };
console.log(hashTable.search('apple'));  // Output: 10

Conclusion​

Search is one of the primary operations in a hash table, allowing fast retrieval of data associated with a key.