Create singly_linked_list.py

Cotains most of the Functions of the singly linked list

Author: Mugendesu

LinkedLists all Types/singly_linked_list.py

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+'''Contains Most of the Singly Linked List functions.\n
+'variable_name' = singly_linked_list.LinkedList() to use this an external module.\n
+'variable_name'.insert_front('element') \t,'variable_name'.insert_back('element'),\n
+'variable_name'.pop_front() are some of its functions.\n
+To print all of its Functions use print('variable_name'.__dir__()).\n
+Note:- 'variable_name' = singly_linked_list.LinkedList() This line is Important before using any of the function.
+
+Author :- Mugen https://github.com/Mugendesu 
+'''
+
+class Node:
+    def __init__(self, val=None , next = None ):
+        self.data = val
+        self.next = next
+
+class LinkedList:
+    
+    def __init__(self):
+        self.head = self.tail = None
+        self.length = 0 
+
+    def insert_front(self , data):
+        node = Node(data , self.head)
+        if self.head == None:
+            self.tail = node
+        self.head = node
+        self.length += 1
+        
+    def insert_back(self , data):
+        node = Node(data )
+        if self.head == None:
+            self.tail = self.head = node
+            self.length += 1
+        else:
+            self.tail.next = node
+            self.tail = node
+            self.length += 1
+    
+    def insert_values(self , data_values : list):
+        self.head = self.tail = None
+        self.length = 0
+        for data in data_values:
+            self.insert_back(data)
+    
+    def pop_front(self):
+        if not self.head:
+            print('List is Empty!')
+            return
+        
+        temp = self.head
+        self.head = self.head.next
+        temp.next = None
+        self.length -= 1
+    
+    def pop_back(self):
+        if not self.head:
+            print('List is Empty!')
+            return
+        
+        temp = self.head
+        while temp.next != self.tail:
+            temp = temp.next
+        self.tail = temp
+        temp.next = None
+        self.length -= 1
+    
+    def print(self):
+        if self.head is None:
+            print('Linked List is Empty!')
+            return
+
+        temp = self.head
+        while temp:
+            print(f'{temp.data} ->' , end = ' ')
+            temp = temp.next
+        print('NULL')
+ 
+    def len(self):
+        return self.length # O(1) length calculation
+        # if self.head is None:
+        #     return 0
+        # count = 0
+        # temp = self.head
+        # while temp:
+        #     count += 1
+        #     temp = temp.next
+        # return count
+    
+    def remove_at(self , idx):
+        if idx < 0 or self.len() <= idx:
+            raise Exception('Invalid Position')
+        if idx == 0:
+            self.head = self.head.next
+            self.length -= 1
+            return    
+        temp = self.head
+        dist = 0
+        while dist != idx-1:
+            dist += 1
+            temp = temp.next
+        temp.next = temp.next.next
+        self.length -= 1
+        
+    def insert_at(self , idx : int , data ):
+        if idx < 0 or self.len() < idx:
+            raise Exception('Invalid Position')
+        if idx == 0:
+            self.insert_front(data)
+            return
+        temp = self.head
+        dist = 0
+        while dist != idx-1:
+            dist += 1
+            temp = temp.next
+        node = Node(data , temp.next)
+        temp.next = node
+        self.length += 1
+    
+    def insert_after_value(self , idx_data , data):
+        if not self.head : # For Empty List case
+            print('List is Empty!')
+            return
+        
+        if self.head.data == idx_data: # To insert after the Head Element 
+            self.insert_at(1 , data)
+            return
+        temp = self.head
+        while temp:
+            if temp.data == idx_data:
+                node = Node(data , temp.next)
+                temp.next = node
+                self.length += 1
+                return
+            temp = temp.next
+        print('The Element is not in the List!')
+        
+    def remove_by_value(self , idx_data):
+        temp = self.head
+        if temp.data == idx_data:
+            self.head = self.head.next
+            self.length -= 1  
+            temp.next = None
+            return
+        while temp.next != None:
+            if temp.next.data == idx_data:
+                temp.next = temp.next.next  
+                self.length -= 1
+                return
+            
+            temp = temp.next
+        print('Element is not in the List!')
+
+    def index(self , data):
+        '''Returns the index of the Element'''
+        if not self.head :
+            print('List is Empty!')
+            return
+        idx = 0
+        temp = self.head
+        while temp:
+            if temp.data == data: return idx
+            temp = temp.next
+            idx += 1
+        print('The Element is not in the List!')
+
+    def search(self , idx):
+        '''Returns the Element at the Given Index'''
+        if self.len() == 0 or idx >= self.len():
+            raise Exception('Invalid Position')
+            return
+        temp = self.head
+        curr_idx = 0
+        while temp:
+            if curr_idx == idx:
+                return temp.data
+            temp = temp.next
+            curr_idx += 1
+    
+    def reverse(self):
+        if not self.head:
+            print('The List is Empty!')
+            return
+        prev = c_next = None
+        curr = self.head
+        while curr != None:
+            c_next = curr.next
+            curr.next = prev
+            prev = curr
+            curr = c_next
+        self.tail = self.head
+        self.head = prev
+        
+    def mid_element(self):
+        if not self.head:
+            print('List is Empty!')
+            return
+        slow = self.head.next
+        fast = self.head.next.next
+        while fast != None and fast.next != None:
+            slow = slow.next
+            fast = fast.next.next
+        return slow.data
+
+    def __dir__(self):
+        funcs = ['insert_front', 'insert_back','pop_front','pop_back','print','len','length','remove_at','insert_after_value','index','search','reverse','mid_element','__dir__']
+        return funcs
+    
+def main():
+    ll : Node = LinkedList()
+
+    # # ll.insert_front(1)        
+    # # ll.insert_front(2)        
+    # # ll.insert_front(3)
+    # # ll.insert_back(0)
+    # ll.insert_values(['ZeroTwo' , 'Asuna' , 'Tsukasa' , 'Seras' ])
+    # # ll.remove_at(3)
+    # ll.insert_at(2 , 'Raeliana')
+    # # ll.pop_front()
+    # ll.insert_after_value('Raeliana' , 'MaoMao')
+    # # print(ll.search(5))
+    # ll.remove_by_value('Tsukasa')
+    # ll.reverse()
+    
+    # ll.print()
+    # print(ll.mid_element())
+    # print(ll.length)
+    print(ll.__dir__())  
+    
+    
+    
+    
+          
+if __name__ == '__main__':
+    main()