put('hello', 'world') # Add a new key-value pair. >>> len(table) # Return the number of key-value pairs stored in the map. 1 >>> table.get('hello') # Get value by key. 'world' >>> del table['hello'] # Equivalent to `table.del_('hello')`, deleting key-value pair. >>> table.get('hello') is None
HashTable Data Type:
By having each bucket contain a linked list of elements that are hashed to that bucket.
Usage:
>>> table = SeparateChainingHashTable() # Create a new, empty map.
>>> table.put('hello', 'world') # Add a new key-value pair.
>>> len(table) # Return the number of key-value pairs stored in the map.
1
>>> table.get('hello') # Get value by key.
'world'
>>> del table['hello'] # Equivalent to `table.del_('hello')`, deleting key-value pair.
>>> table.get('hello') is None # Return `None` if a key doesn't exist.
True
"""
_empty = None
def __init__(self, size=11):
self.size = size
self._len = 0
self._table = [self._empty] * size
def put(self, key, value):
hash_ = self.hash(key)
node_ = self._table[hash_]
if node_ is self._empty:
self._table[hash_] = Node(key, value)
else:
while node_.next is not None:
if node_.key == key:
node_.value = value
return
node_ = node_.next
node_.next = Node(key, value)
self._len += 1
def get(self, key):
hash_ = self.hash(key)
node_ = self._table[hash_]
while node_ is not self._empty:
if node_.key == key:
return node_.value
node_ = node_.next
return None
def del_(self, key):
hash_ = self.hash(key)
node_ = self._table[hash_]
pre_node = None
while node_ is not None:
if node_.key == key:
if pre_node is None:
self._table[hash_] = node_.next
else:
pre_node.next = node_.next
self._len -= 1
pre_node = node_
node_ = node_.next
def hash(self, key):
return hash(key) % self.size
def __len__(self):
return self._len
def __getitem__(self, key):
return self.get(key)
def __delitem__(self, key):
return self.del_(key)
def __setitem__(self, key, value):.
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