A hash table is a data structure that stores key-value pairs in an associative manner. It allows for efficient data retrieval using a hash function to compute indexes.

How It Works

  1. Hash Function: Converts keys into indexes (e.g., hash(key) % size).
  2. Collision Handling: Resolves conflicts using chaining or open addressing.
  3. Insertion/Retrieval: O(1) average time complexity for these operations.
# Python example: Using dict as a hash table
hash_table = {}
hash_table["name"] = "Alice"
print(hash_table.get("name"))  # Output: Alice

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Use Cases

  • Storing user sessions in web applications
  • Implementing caching mechanisms
  • Building dictionaries in programming languages

Implementation Tips

  • Use a good hash function to minimize collisions
  • Resize the table when load factor exceeds a threshold
  • Choose between chaining and open addressing based on use case

Further Reading

For a deeper dive into hash table optimizations, check our guide on hash_table_performance.
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hash_table_structure
collisions_resolution