This notebook was prepared by Donne Martin. Source and license info is on GitHub.
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%%writefile linked_list.py
class Node(object):
def __init__(self, data, next=None):
self.next = next
self.data = data
def __str__(self):
return self.data
class LinkedList(object):
def __init__(self, head=None):
self.head = head
def __len__(self):
curr = self.head
counter = 0
while curr is not None:
counter += 1
curr = curr.next
return counter
def insert_to_front(self, data):
if data is None:
return None
node = Node(data, self.head)
self.head = node
return node
def append(self, data):
if data is None:
return None
node = Node(data)
if self.head is None:
self.head = node
return node
curr_node = self.head
while curr_node.next is not None:
curr_node = curr_node.next
curr_node.next = node
return node
def find(self, data):
if data is None:
return None
curr_node = self.head
while curr_node is not None:
if curr_node.data == data:
return curr_node
curr_node = curr_node.next
return None
def delete(self, data):
if data is None:
return
if self.head is None:
return
if self.head.data == data:
self.head = self.head.next
return
prev_node = self.head
curr_node = self.head.next
while curr_node is not None:
if curr_node.data == data:
prev_node.next = curr_node.next
return
prev_node = curr_node
curr_node = curr_node.next
def delete_alt(self, data):
if data is None:
return
if self.head is None:
return
curr_node = self.head
if curr_node.data == data:
curr_node = curr_node.next
return
while curr_node.next is not None:
if curr_node.next.data == data:
curr_node.next = curr_node.next.next
return
curr_node = curr_node.next
def print_list(self):
curr_node = self.head
while curr_node is not None:
print(curr_node.data)
curr_node = curr_node.next
def get_all_data(self):
data = []
curr_node = self.head
while curr_node is not None:
data.append(curr_node.data)
curr_node = curr_node.next
return data
Overwriting linked_list.py
%run linked_list.py
%%writefile test_linked_list.py
import unittest
class TestLinkedList(unittest.TestCase):
def test_insert_to_front(self):
print('Test: insert_to_front on an empty list')
linked_list = LinkedList(None)
linked_list.insert_to_front(10)
self.assertEqual(linked_list.get_all_data(), [10])
print('Test: insert_to_front on a None')
linked_list.insert_to_front(None)
self.assertEqual(linked_list.get_all_data(), [10])
print('Test: insert_to_front general case')
linked_list.insert_to_front('a')
linked_list.insert_to_front('bc')
self.assertEqual(linked_list.get_all_data(), ['bc', 'a', 10])
print('Success: test_insert_to_front\n')
def test_append(self):
print('Test: append on an empty list')
linked_list = LinkedList(None)
linked_list.append(10)
self.assertEqual(linked_list.get_all_data(), [10])
print('Test: append a None')
linked_list.append(None)
self.assertEqual(linked_list.get_all_data(), [10])
print('Test: append general case')
linked_list.append('a')
linked_list.append('bc')
self.assertEqual(linked_list.get_all_data(), [10, 'a', 'bc'])
print('Success: test_append\n')
def test_find(self):
print('Test: find on an empty list')
linked_list = LinkedList(None)
node = linked_list.find('a')
self.assertEqual(node, None)
print('Test: find a None')
head = Node(10)
linked_list = LinkedList(head)
node = linked_list.find(None)
self.assertEqual(node, None)
print('Test: find general case with matches')
head = Node(10)
linked_list = LinkedList(head)
linked_list.insert_to_front('a')
linked_list.insert_to_front('bc')
node = linked_list.find('a')
self.assertEqual(str(node), 'a')
print('Test: find general case with no matches')
node = linked_list.find('aaa')
self.assertEqual(node, None)
print('Success: test_find\n')
def test_delete(self):
print('Test: delete on an empty list')
linked_list = LinkedList(None)
linked_list.delete('a')
self.assertEqual(linked_list.get_all_data(), [])
print('Test: delete a None')
head = Node(10)
linked_list = LinkedList(head)
linked_list.delete(None)
self.assertEqual(linked_list.get_all_data(), [10])
print('Test: delete general case with matches')
head = Node(10)
linked_list = LinkedList(head)
linked_list.insert_to_front('a')
linked_list.insert_to_front('bc')
linked_list.delete('a')
self.assertEqual(linked_list.get_all_data(), ['bc', 10])
print('Test: delete general case with no matches')
linked_list.delete('aa')
self.assertEqual(linked_list.get_all_data(), ['bc', 10])
print('Success: test_delete\n')
def test_len(self):
print('Test: len on an empty list')
linked_list = LinkedList(None)
self.assertEqual(len(linked_list), 0)
print('Test: len general case')
head = Node(10)
linked_list = LinkedList(head)
linked_list.insert_to_front('a')
linked_list.insert_to_front('bc')
self.assertEqual(len(linked_list), 3)
print('Success: test_len\n')
def main():
test = TestLinkedList()
test.test_insert_to_front()
test.test_append()
test.test_find()
test.test_delete()
test.test_len()
if __name__ == '__main__':
main()
Overwriting test_linked_list.py
%run -i test_linked_list.py
Test: insert_to_front on an empty list Test: insert_to_front on a None Test: insert_to_front general case Success: test_insert_to_front Test: append on an empty list Test: append a None Test: append general case Success: test_append Test: find on an empty list Test: find a None Test: find general case with matches Test: find general case with no matches Success: test_find Test: delete on an empty list Test: delete a None Test: delete general case with matches Test: delete general case with no matches Success: test_delete Test: len on an empty list Test: len general case Success: test_len