odilson-dev / hashmap

The Hashmap Project is an assignment from TOP's curriculum, where participants work on creating and implementing a hashmap data structure as part of their learning exercises.

HashMap Implementation in Ruby

This is an exercise that implements a hash map structure in the Ruby language. Done as part of The Odin Project curriculum.

This repository contains a comprehensive implementation of a hash map in Ruby, featuring a robust linked list for handling collisions. The implementation is designed with scalability and simplicity in mind, making it suitable for a wide range of applications.

Files Included

linked_list.rb

This file defines the LinkedList class, a fundamental component for handling collisions in the hash map. The linked list is a dynamic data structure that allows for efficient insertion and retrieval of key-value pairs. Each node in the linked list contains a key, data, and a reference to the next node.

hashmap.rb

The HashMap class is the core component of this repository, showcasing a powerful hash map implementation utilizing the linked list for managing collisions. The hash map is initialized with a fixed number of buckets (default: 16) to store key-value pairs efficiently. It provides methods for setting key-value pairs, retrieving values by key, checking for key existence, clearing all elements, and obtaining arrays of keys, values, and entries.

node.rb

The Node class defines the structure of a node in the linked list. Each node encapsulates a key, data, and a reference to the next node. This class is an integral part of the linked list and contributes to the overall functionality of the hash map.

Features

• Collision Handling: Utilizes a linked list to manage collisions efficiently.
• Dynamic Sizing: The number of buckets in the hash map is customizable for optimization.
• Key-Value Operations: Provides methods for setting, getting, and checking the existence of key-value pairs.
• Clearing Elements: Clears all elements from the hash map.

Usage Example

# Create a new HashMap
my_hash_map = HashMap.new

# Set key-value pairs
my_hash_map.set("name", "John")
my_hash_map.set("age", 25)
my_hash_map.set("city", "New York")

# Retrieve values
puts "Name: #{my_hash_map.get("name")}"
puts "Age: #{my_hash_map.get("age")}"
puts "City: #{my_hash_map.get("city")}"

# Display all keys, values, and entries
puts "All Keys: #{my_hash_map.keys}"
puts "All Values: #{my_hash_map.values}"
puts "All Entries: #{my_hash_map.entries}"

# Returns true or false based on whether or not the key is in the hash map
puts my_hash_map.key?("name") #true
puts my_hash_map.key?("age") #true
puts my_hash_map.key?("city") #true

puts my_hash_map.key?("hello") #false

# returns the number of stored keys in the hash map
puts my_hash_map.length # 3

my_hash_map.remove("name")
puts my_hash_map.length # 2
puts my_hash_map.get("name") # nil
puts my_hash_map.key?("name") # false

p my_hash_map.keys ["age", "city"]


# removes all entries in the hash map.
my_hash_map.clear

puts my_hash_map.length # 0
puts my_hash_map.keys # []