python program to select random node

1.linked list/random_node_from_SLL.py

@@ -0,0 +1,80 @@
+
+# coding: utf-8
+
+# In[7]:
+
+
+import random 
+
+# Creation of a node
+class Node: 
+
+    # Constructor to initialize the node object 
+    def __init__(self, data): 
+        self.data= data 
+        self.next = None
+
+# Linking of nodes        
+class LinkedList: 
+
+    # function to initialize head 
+    def __init__(self): 
+        self.head = None
+
+    # function to print a random node from a linkd list 
+    def printRandom(self): 
+
+        # Checks if list is empty  
+        if self.head is None: 
+            return
+        if self.head and not self.head.next: 
+            print("Randomly selected key is %d" %(self.head.data))
+
+        # Use a different seed value so that we don't get  
+        # same result each time we run this program 
+        random.seed() 
+
+        # Initialize result as first node 
+        result = self.head.data 
+
+        current = self.head.next 
+        n = 2 
+        while(current is not None): 
+
+            if (random.randrange(n) == 0 ): 
+                result = current.data  
+
+            # Move to next node 
+            current = current.next
+            n += 1
+
+        print ("Randomly selected key is %d" %(result))
+
+    # function to insert a new node at the beginning 
+    def push(self, new_data): 
+        new_node = Node(new_data) 
+        new_node.next = self.head 
+        self.head = new_node 
+
+    # Utility function to print the LinkedList 
+    def printList(self): 
+        temp = self.head 
+        while(temp): 
+            print (temp.data), 
+            temp = temp.next
+
+
+llist = LinkedList() 
+llist.push(51) 
+llist.push(100) 
+llist.push(60) 
+llist.push(89) 
+llist.push(32)
+llist.push(87) 
+llist.push(55) 
+llist.push(72)
+llist.push(90) 
+llist.push(93) 
+llist.push(40)
+llist.printRandom() 
+