Write a Python program to search a specific item in a given doubly linked list and return true if the item is found otherwise return false.
Answers
SOURCE CODE:-
class Node(object):
# Singly linked node
def __init__(self, data=None, next=None, prev=None):
self.data = data
self.next = next
self.prev = prev
class doubly_linked_list(object):
def __init__(self):
self.head = None
self.tail = None
self.count = 0
def append_item(self, data):
# Append an item
new_item = Node(data, None, None)
if self.head is None:
self.head = new_item
self.tail = self.head
else:
new_item.prev = self.tail
self.tail.next = new_item
self.tail = new_item
self.count += 1
def iter(self):
# Iterate the list
current = self.head
while current:
item_val = current.data
current = current.next
yield item_val
def print_foward(self):
for node in self.iter():
print(node)
def insert_start(self, data):
if self.head is not None:
new_node = Node(data, None, None)
new_node.next = self.head
self.head.prev = new_node
self.head = new_node
self.count += 1
items = doubly_linked_list()
items.append_item('PHP')
items.append_item('Python')
items.append_item('C#')
items.append_item('C++')
items.append_item('Java')
items.append_item('SQL')
print("Original list:")
items.print_foward()
print("\nAppend item in front of the list:")
items.insert_start("Perl")
items.print_foward()
class Node(object): # Singly linked node def __init__(self, data=None, next=None, prev=None): self.data = data self.next = next self.prev = prev class doubly_linked_list(object): def __init__(self): self.head = None self.tail = None self.count = 0 def append_item(self, data): # Append an item new_item = Node(data, None, None) if self.head is None: self.head = new_item self.tail = self.head else: new_item.prev = self.tail self.tail.next = new_item self.tail = new_item self.count += 1 def iter(self): # Iterate the list current = self.head while current: item_val = current.data current = current.next yield item_val def print_foward(self): for node in self.iter(): print(node) def search_item(self, val): for node in self.iter(): if val == node: return True return False items = doubly_linked_list() items.append_item('PHP') items.append_item('Python') items.append_item('C#') items.append_item('C++') items.append_item('Java') items.append_item('SQL') print("Original list:") items.print_foward() print("\n") if items.search_item('SQL'): print("True") else: print("False") if items.search_item('C+'): print("True") else: print("False")
Sample Output:
Original list: PHP Python C# C++ Java SQL True False
Flowchart:
Python Code Editor:
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Python: Using list comprehensions to shorten for loops
x = [1, 2, 3, 4, 5] result = [] for idx in range(len(x)): result.append(x[idx] * 2) result
Output:
[2, 4, 6, 8, 10] [(element * 2) for element in x]
Output:
[2, 4, 6, 8, 10]