Implementing Map using an Array and Simple Hashing

readme.md

Overview

This is a simple implementation of a Map using a simple Hashing Function and an Array (of fixed size) as Storage

• Key Type: String
• Value Type: Any

Warning

• No Hash Collision Management yet, just Hash Collision Detection

example_hash.py

# Specs for Naive Hashing 
# - Input: String 
# - Output: Array id 
# - Naive Hashing Function: sum all the string letters and mod for array size to get an id 

def hash_str(in_str, in_lin_storage_size): 
    full_hash_val=0
    if(type(in_str) is not str): 
        raise(ValueError("Arg1 needs to be string"))
    for c in in_str: 
        #print("Char " + str(c))
        full_hash_val += ord(c)
    final_hash_val = full_hash_val % in_lin_storage_size
    #print("Full Hash is " + str(full_hash_val) + ", Final Hash Val is " + str(final_hash_val))
    return final_hash_val
        

class MyMap: 
    def __init__(self, size): 
        self.__storage__ = [None] * size
    def size(self): 
        return len(self.__storage__)
    def insert(self, key, value): 
        h = hash_str(key, len(self.__storage__))
        if(self.__storage__[h] is not None): 
            raise(ValueError("Collision Detected"))
        else: 
            self.__storage__[h] = value 
    def get(self, key): 
        h = hash_str(key, len(self.__storage__))
        return self.__storage__[h]

# Print Your code here
hash_str("ciao bello", 100)

a = MyMap(5)
print("a.size=" + str(a.size()))


a.insert("ciao", 5)
a.insert("test", 11)
print("a['ciao'] = " + str(a.get("ciao")))
print("a['test'] = " + str(a.get("test")))
print("a['what'] = " + str(a.get("what")))