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🍒 Watch Youtube
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👉 Read "Grokking Algorithms"
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pythonpractice
# Array
import array
array1 = array.array('i', [10, 20, 30, 40, 50]) # integer (2-byte) array
# Traverse − print all the array elements one by one
for x in array1:
print(x)
print('\n')
# Accessing Array Element
print (array1[0])
print (array1[2])
print('\n')
# Insertion − add an element at the given index
array1.insert(1, 60)
for x in array1:
print(x)
print('\n')
# Deletion − delete an element at the given index
array1.remove(40)
for x in array1:
print(x)
print('\n')
# Search − search an element using the given index or by the value
print (array1.index(20)) # if there is no searching item exists, error (exception) will occur
print('\n')
# Update − update an element at the given index
array1[2] = 80
for x in array1:
print(x)- 🐍
pythonpractice
# Linked List
# In fact, you don't need to design a class for linked list.
# 'Python list' is alread designed for linked list.
# However, it is good to know how 'Python list' works as a linked list by writing your own code.
# Creation of Linked list and traverse
class Node:
def __init__(self, data=None):
self.data = data
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def list_print(self):
current_node = self.head
while current_node is not None:
print(current_node.data)
current_node = current_node.next
# Todo list test
todo_node0 = Node("BRUNCH")
todo_node1 = Node("BOCCE")
todo_node2 = Node("DRINK TEA")
todo_list = LinkedList()
todo_list.head = todo_node0
todo_node0.next = todo_node1
todo_node1.next = todo_node2
todo_list.list_print()- 🐍
pythonpractice
# Linked List
# Insert a node at the beginning
class Node:
def __init__(self, data=None):
self.data = data
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def list_print(self):
current_node = self.head
while current_node is not None:
print(current_node.data)
current_node = current_node.next
def insert_at_beginning(self, data):
new_node = Node(data)
new_node.next = self.head
self.head = new_node
# Todo list test
todo_node0 = Node("BRUNCH")
todo_node1 = Node("BOCCE")
todo_node2 = Node("DRINK TEA")
todo_list = LinkedList()
todo_list.head = todo_node0
todo_node0.next = todo_node1
todo_node1.next = todo_node2
todo_list.insert_at_beginning("BUY TEA")
todo_list.list_print()- 🐍
pythonpractice
# Linked List
# Inserting a node at the end
class Node:
def __init__(self, data=None):
self.data = data
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def list_print(self):
current_node = self.head
while current_node is not None:
print(current_node.data)
current_node = current_node.next
def insert_at_beginning(self, data):
new_node = Node(data)
new_node.next = self.head
self.head = new_node
def insert_at_end(self, data):
new_node = Node(data)
if self.head is None:
self.head = new_node
return
last_node = self.head
while last_node.next is not None:
last_node = last_node.next
last_node.next = new_node
# Todo list test
todo_node0 = Node("BRUNCH")
todo_node1 = Node("BOCCE")
todo_node2 = Node("DRINK TEA")
todo_list = LinkedList()
todo_list.head = todo_node0
todo_node0.next = todo_node1
todo_node1.next = todo_node2
todo_list.insert_at_end("BUY TEA")
todo_list.list_print()- 🐍
pythonpractice
# Linked List
# Inserting a node in the middle
class Node:
def __init__(self, data=None):
self.data = data
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def list_print(self):
current_node = self.head
while current_node is not None:
print(current_node.data)
current_node = current_node.next
def insert_at_beginning(self, data):
new_node = Node(data)
new_node.next = self.head
self.head = new_node
def insert_at_end(self, data):
new_node = Node(data)
if self.head is None:
self.head = new_node
return
last_node = self.head
while last_node.next is not None:
last_node = last_node.next
last_node.next = new_node
def insert_in_middle(self, middle_node, data):
if middle_node is None:
print("There is no such a middle node!")
return
new_node = Node(data)
new_node.next = middle_node.next
middle_node.next = new_node
# Todo list test
todo_node0 = Node("BRUNCH")
todo_node1 = Node("BOCCE")
todo_node2 = Node("DRINK TEA")
todo_list = LinkedList()
todo_list.head = todo_node0
todo_node0.next = todo_node1
todo_node1.next = todo_node2
todo_list.insert_in_middle(todo_node1, "BUY TEA")
todo_list.list_print()- 🐍
pythonpractice
# Linked List
# Removing a node
class Node:
def __init__(self, data=None):
self.data = data
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def list_print(self):
current_node = self.head
while current_node is not None:
print(current_node.data)
current_node = current_node.next
def insert_at_beginning(self, data):
new_node = Node(data)
new_node.next = self.head
self.head = new_node
def insert_at_end(self, data):
new_node = Node(data)
if self.head is None:
self.head = new_node
return
last_node = self.head
while last_node.next is not None:
last_node = last_node.next
last_node.next = new_node
def insert_in_middle(self, middle_node, data):
if middle_node is None:
print("There is no such a middle node!")
return
new_node = Node(data)
new_node.next = middle_node.next
middle_node.next = new_node
def remove(self, data):
previous_node = None
current_node = self.head
if current_node is None:
return
if current_node.data == data:
self.head = current_node.next
current_node = None
return
while current_node is not None:
if current_node.data == data:
break
previous_node = current_node
current_node = current_node.next
if current_node == None:
return
else:
previous_node.next = current_node.next
current_node = None
# Todo list test
todo_node0 = Node("BRUNCH")
todo_node1 = Node("BOCCE")
todo_node2 = Node("DRINK TEA")
todo_list = LinkedList()
todo_list.head = todo_node0
todo_node0.next = todo_node1
todo_node1.next = todo_node2
todo_list.remove("BOCCE")
todo_list.list_print()