def __init__(self, data):
"""
Initialize the iterator before the first entry in linkedhashtable
:param data: the linkedhashtable class
"""
self.i = ChainNode("")
self.i.setLink(data._front)
class Iterator:
"""
The internal iterator class
"""
__slots__ = "i"
def __init__(self, data):
"""
Initialize the iterator before the first entry in linkedhashtable
:param data: the linkedhashtable class
"""
self.i = ChainNode("")
self.i.setLink(data._front)
def __iter__(self):
"""
Define the iterator itself
:return: the iterator itself
"""
return self
def __next__(self):
"""
Get the next entry in the linkedhashtable class till the last entry
:return: the next entry
"""
if not self.i.hasLink():
raise StopIteration()
self.i = self.i.getLink()
return self.i
def remove(self, obj):
"""
Remove a spcific entry(obj) form the hashtable
:param obj: the entry being removed
:return: the removed entry
"""
if self.contains(obj):
if self.sizeOff():
self.rehash()
toRemoved = ChainNode(obj)
key = toRemoved.getKey(self._capacity)
temp = self._list[key]
temp_back = temp
# if the entry to be removed is the first item in this linked list
if str(temp) == obj:
self._list[key] = self._list[key].getChain()
temp.setChain(None)
# else the entry to be removed is in other position than the first
else:
while not temp.getChain() is None:
temp = temp.getChain()
if str(temp) == obj:
temp_back.setChain(temp.getChain())
temp.setChain(None)
break
temp_back = temp_back.getChain()
# if the entry to be removed is the only one left in hashtable
if temp.getPrevious() is None and temp.getLink() is None:
self._front = None
self._back = None
# if the entry to be removed is front
elif temp.getPrevious() is None:
self._front = temp.getLink()
temp.getLink().setPrevious(None)
temp.setLink(None)
# if the entry to be removed is back
elif temp.getLink() is None:
self._back = temp.getPrevious()
temp.getPrevious().setLink(None)
temp.setPrevious(None)
# if the entry to be removed is in the middle
else:
temp.getPrevious().setLink(temp.getLink())
temp.getLink().setPrevious(temp.getPrevious())
temp.setPrevious(None)
temp.setLink(None)
self._size -= 1
return temp
def test_add(self):
"""
Test the add and _add function
"""
e1 = ChainNode("we")
e2 = ChainNode("are")
e3 = ChainNode("the")
e4 = ChainNode("light")
e5 = ChainNode("miwa")
table = Linkedhashtable()
self.assertEqual(str(table), "front -> <- back")
table.add(e1)
table.add(e2)
table.add(e3)
table.add(e4)
table.add(e5)
self.assertEqual(str(table), "front -> we are the light miwa <- back")
def contains(self, obj):
"""
Check if an entry(obj) is in hashtable
:param obj: the entry being checked
:return: true if this entry is found
"""
toSearch = ChainNode(obj)
key = toSearch.getKey(self._capacity)
temp = self._list[key]
if self._list[key] is None:
return False
elif str(temp) == obj:
return True
else:
while not temp.getChain() is None:
temp = temp.getChain()
if str(temp) == obj:
return True
return False
def test_contains(self):
"""
Test the contains function
"""
e1 = ChainNode("we")
e2 = ChainNode("are")
e3 = ChainNode("the")
e4 = ChainNode("light")
e5 = ChainNode("miwa")
table = Linkedhashtable()
table.add(e1)
table.add(e2)
table.add(e3)
table.add(e4)
table.add(e5)
self.assertTrue(table.contains("we"))
self.assertTrue(table.contains("the"))
self.assertTrue(table.contains("miwa"))
self.assertFalse(table.contains("you"))
self.assertFalse(table.contains("wee"))
def test_iterator(self):
"""
Test the iterator class
"""
e1 = ChainNode("we")
e2 = ChainNode("are")
e3 = ChainNode("the")
e4 = ChainNode("light")
e5 = ChainNode("miwa")
table = Linkedhashtable()
table.add(e1)
table.add(e2)
table.add(e3)
table.add(e4)
table.add(e5)
temp = table.__iter__()
self.assertEqual(str(temp.__next__()), "we")
self.assertEqual(str(temp.__next__()), "are")
self.assertEqual(str(temp.__next__()), "the")
self.assertEqual(str(temp.__next__()), "light")
self.assertEqual(str(temp.__next__()), "miwa")
def test_rehash(self):
"""
Test the rehash, sizeOver, sizeOff, and _remove functions
"""
e1 = ChainNode("rise")
e2 = ChainNode("on")
e3 = ChainNode("up")
e4 = ChainNode("till")
e5 = ChainNode("ya")
e6 = ChainNode("touching")
e7 = ChainNode("moon")
e8 = ChainNode("we")
e9 = ChainNode("are")
e10 = ChainNode("the")
e11 = ChainNode("light")
e12 = ChainNode("miwa")
table = Linkedhashtable(6, 0.8)
self.assertEqual(table._size, 0)
self.assertEqual(table._capacity, 6)
self.assertEqual(len(table._list), 6)
table.add(e1)
table.add(e2)
table.add(e3)
table.add(e4)
table.add(e5)
table.add(e6)
table.add(e7)
table.add(e8)
table.add(e9)
table.add(e10)
table.add(e11)
table.add(e12)
self.assertEqual(table._size, 12)
self.assertEqual(table._capacity, 24)
self.assertEqual(len(table._list), 24)
self.assertEqual(
str(table), "front -> rise on up till ya touching moon"
" we are the light miwa <- back")
table.remove("ya")
table.remove("up")
table.remove("are")
table.remove("on")
table.remove("miwa")
table.remove("moon")
table.remove("rise")
table.remove("the")
self.assertEqual(table._size, 4)
self.assertEqual(table._capacity, 12)
self.assertEqual(len(table._list), 12)
self.assertEqual(str(table), "front -> till touching we light <- back")
table.remove("we")
self.assertEqual(table._size, 3)
self.assertEqual(table._capacity, 12)
self.assertEqual(len(table._list), 12)
self.assertEqual(str(table), "front -> till touching light <- back")
table.remove("till")
self.assertEqual(table._size, 2)
self.assertEqual(table._capacity, 6)
self.assertEqual(len(table._list), 6)
self.assertEqual(str(table), "front -> touching light <- back")
table.remove("light")
self.assertEqual(table._size, 1)
self.assertEqual(table._capacity, 3)
self.assertEqual(len(table._list), 3)
self.assertEqual(str(table), "front -> touching <- back")
table.remove("touching")
self.assertEqual(table._size, 0)
self.assertEqual(table._capacity, 3)
self.assertEqual(len(table._list), 3)
self.assertEqual(str(table), "front -> <- back")