python linked list

1class Node:
2    def __init__(self, data = None, next_node = None):
3        self.data = data
4        self.nextNode = next_node
5
6    def get_data(self):
7        return self.data
8
9    def set_data(self, data):
10        self.data = data
11
12    def get_nextNode(self):
13        return self.nextNode
14
15    def set_nextNode(self, nextNode):
16        self.nextNode = nextNode
17
18
19class LinkedList:
20    def __init__(self, head = None):
21        self.head = head
22
23
24    def add_Node(self, data):
25        # if empty
26        if self.head == None:
27            self.head = Node(data)
28
29
30        # not empty
31        else:
32            curr_Node = self.head
33            
34            # if node added is at the start
35            if data < curr_Node.get_data():
36                self.head = Node(data, curr_Node)
37                
38            # not at start
39            else:
40                while data > curr_Node.get_data() and curr_Node.get_nextNode() != None:
41                    prev_Node = curr_Node
42                    curr_Node = curr_Node.get_nextNode()
43
44                # if node added is at the middle
45                if data < curr_Node.get_data():
46                    prev_Node.set_nextNode(Node(data, curr_Node))
47                
48
49                # if node added is at the last
50                elif data > curr_Node.get_data() and curr_Node.get_nextNode() == None:
51                    curr_Node.set_nextNode(Node(data))
52
53
54
55    def search(self, data):
56        curr_Node = self.head
57        while curr_Node != None:
58            if data == curr_Node.get_data():
59                return True
60
61            else:
62                curr_Node = curr_Node.get_nextNode()
63
64        return False
65
66
67    def delete_Node(self, data):
68        if self.search(data):
69            # if data is found
70
71            curr_Node = self.head
72            #if node to be deleted is the first node
73            if curr_Node.get_data() == data:
74                self.head = curr_Node.get_nextNode()
75
76            else:
77                while curr_Node.get_data() != data:
78                    prev_Node = curr_Node
79                    curr_Node = curr_Node.get_nextNode()
80                    
81                #node to be deleted is middle
82                if curr_Node.get_nextNode() != None:
83                    prev_Node.set_nextNode(curr_Node.get_nextNode())
84
85                # node to be deleted is at the end
86                elif curr_Node.get_nextNode() == None:
87                    prev_Node.set_nextNode(None)
88
89        else:
90            return "Not found."
91
92    def return_as_lst(self):
93        lst = []
94        curr_Node = self.head
95        while curr_Node != None:
96            lst.append(curr_Node.get_data())
97            curr_Node = curr_Node.get_nextNode()
98
99        return lst
100
101    def size(self):
102        curr_Node = self.head
103        count = 0
104        while curr_Node:
105            count += 1
106            curr_Node = curr_Node.get_nextNode()
107        return count
108
109      
110## TEST CASES #
111test1 = LinkedList()
112test2 = LinkedList()
113test1.add_Node(20)
114test1.add_Node(15)
115test1.add_Node(13)
116test1.add_Node(14)
117test1.delete_Node(17)
118print(test1.return_as_lst())
119print(test2.size())

1# Linked list operations in Python
2
3
4# Create a node
5class Node:
6    def __init__(self, data):
7        self.data = data
8        self.next = None
9
10
11class LinkedList:
12
13    def __init__(self):
14        self.head = None
15
16    # Insert at the beginning
17    def insertAtBeginning(self, new_data):
18        new_node = Node(new_data)
19
20        new_node.next = self.head
21        self.head = new_node
22
23    # Insert after a node
24    def insertAfter(self, prev_node, new_data):
25
26        if prev_node is None:
27            print("The given previous node must inLinkedList.")
28            return
29
30        new_node = Node(new_data)
31        new_node.next = prev_node.next
32        prev_node.next = new_node
33
34    # Insert at the end
35    def insertAtEnd(self, new_data):
36        new_node = Node(new_data)
37
38        if self.head is None:
39            self.head = new_node
40            return
41
42        last = self.head
43        while (last.next):
44            last = last.next
45
46        last.next = new_node
47
48    # Deleting a node
49    def deleteNode(self, position):
50
51        if self.head is None:
52            return
53
54        temp = self.head
55
56        if position == 0:
57            self.head = temp.next
58            temp = None
59            return
60
61        # Find the key to be deleted
62        for i in range(position - 1):
63            temp = temp.next
64            if temp is None:
65                break
66
67        # If the key is not present
68        if temp is None:
69            return
70
71        if temp.next is None:
72            return
73
74        next = temp.next.next
75
76        temp.next = None
77
78        temp.next = next
79
80    # Search an element
81    def search(self, key):
82
83        current = self.head
84
85        while current is not None:
86            if current.data == key:
87                return True
88
89            current = current.next
90
91        return False
92
93    # Sort the linked list
94    def sortLinkedList(self, head):
95        current = head
96        index = Node(None)
97
98        if head is None:
99            return
100        else:
101            while current is not None:
102                # index points to the node next to current
103                index = current.next
104
105                while index is not None:
106                    if current.data > index.data:
107                        current.data, index.data = index.data, current.data
108
109                    index = index.next
110                current = current.next
111
112    # Print the linked list
113    def printList(self):
114        temp = self.head
115        while (temp):
116            print(str(temp.data) + " ", end="")
117            temp = temp.next
118
119
120if __name__ == '__main__':
121
122    llist = LinkedList()
123    llist.insertAtEnd(1)
124    llist.insertAtBeginning(2)
125    llist.insertAtBeginning(3)
126    llist.insertAtEnd(4)
127    llist.insertAfter(llist.head.next, 5)
128
129    print('linked list:')
130    llist.printList()
131
132    print("\nAfter deleting an element:")
133    llist.deleteNode(3)
134    llist.printList()
135
136    print()
137    item_to_find = 3
138    if llist.search(item_to_find):
139        print(str(item_to_find) + " is found")
140    else:
141        print(str(item_to_find) + " is not found")
142
143    llist.sortLinkedList(llist.head)
144    print("Sorted List: ")
145    llist.printList()

1pip install llist

1Full Linked List implementation at this link:
2https://github.com/shreyasvedpathak/Data-Structure-Python/tree/master/LinkedList

1class LinkedList(object):
2    def __init__(self, head=None):
3        self.head = head
4
5	# ignored...  answer below
6    def get_position(self, position):
7        counter = 1
8        current = self.head
9        if position < 1:
10            return None
11        while current and counter <= position:
12            if counter == position:
13                return current
14            current = current.next
15            counter += 1
16        return None
17	# ignored...  answer above
181234567891011121314151617

1class Node:
2    def __init__(self, data):
3        self.data = data
4        self.next = None
5
6    def __repr__(self):
7        return self.data
8
9class LinkedList:
10    def __init__(self):
11        self.head = None
12
13    def __repr__(self):
14        node = self.head
15        nodes = []
16        while node is not None:
17            nodes.append(node.data)
18            node = node.next
19        nodes.append("None")
20        return " -> ".join(nodes)
21