ADT_hashmap.py

class HashMap1(object):
    def __init__(self, hashMap={}):
        self.hashMap = hashMap
    
    def add(self, key, value):
        if (key not in self.hashMap):
            self.hashMap[key] = value
            return
        raise Exception("Key is already within our data structure")


    def update(self, key, value):
        if (key in self.hashMap):
            self.hashMap[key] = value
            return
        raise Exception("Key does not exist in our data structure")

    def delete(self, key):
        if (key in self.hashMap):
            self.hashMap.pop(key)
            return
        raise Exception("Key does not exist in our data structure")

class HashTable:
      
    # Create empty bucket list of given size
    def __init__(self, size):
        self.size = size
        self.hash_table = self.create_buckets()
  
    def create_buckets(self):
        return [[] for _ in range(self.size)]
  
    # Insert values into hash map
    def set_val(self, key, val):
        
        # Get the index from the key
        # using hash function
        hashed_key = hash(key) % self.size
          
        # Get the bucket corresponding to index
        bucket = self.hash_table[hashed_key]
  
        found_key = False
        for index, record in enumerate(bucket):
            record_key, record_val = record
              
            # check if the bucket has same key as
            # the key to be inserted
            if record_key == key:
                found_key = True
                break
  
        # If the bucket has same key as the key to be inserted,
        # Update the key value
        # Otherwise append the new key-value pair to the bucket
        if found_key:
            bucket[index] = (key, val)
        else:
            bucket.append((key, val))
  
    # Return searched value with specific key
    def get_val(self, key):
        
        # Get the index from the key using
        # hash function
        hashed_key = hash(key) % self.size
          
        # Get the bucket corresponding to index
        bucket = self.hash_table[hashed_key]
  
        found_key = False
        for index, record in enumerate(bucket):
            record_key, record_val = record
              
            # check if the bucket has same key as 
            # the key being searched
            if record_key == key:
                found_key = True
                break
  
        # If the bucket has same key as the key being searched,
        # Return the value found
        # Otherwise indicate there was no record found
        if found_key:
            return record_val
        else:
            return "No record found"
  
    # Remove a value with specific key
    def delete_val(self, key):
        
        # Get the index from the key using
        # hash function
        hashed_key = hash(key) % self.size
          
        # Get the bucket corresponding to index
        bucket = self.hash_table[hashed_key]
  
        found_key = False
        for index, record in enumerate(bucket):
            record_key, record_val = record
              
            # check if the bucket has same key as
            # the key to be deleted
            if record_key == key:
                found_key = True
                break
        if found_key:
            bucket.pop(index)
        return
  
    # To print the items of hash map
    def __str__(self):
        return "".join(str(item) for item in self.hash_table)
  



if __name__ == '__main__':
    # obj = HashMap1()
    
    # obj.add('key1', 'XYZ')
    # obj.add('key2', 'ABC')
    # obj.delete('key2')
    
    # print(obj.hashMap)
    
    hash_table = HashTable(50)
    
    # insert some values
    hash_table.set_val('gfg@example.com', 'some value')
    print(hash_table)
    print()
    
    hash_table.set_val('portal@example.com', 'some other value')
    print(hash_table)
    print()
    
    # search/access a record with key
    print(hash_table.get_val('portal@example.com'))
    print()
    
    # delete or remove a value
    hash_table.delete_val('portal@example.com')
    print(hash_table)