swap nodes using linked list

Author: raianmol172

swap nodes in linkedlist.py

@@ -0,0 +1,52 @@
+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.next = None
+
+class Linkedlist:
+    def __init__(self):
+        self.head = None
+
+    def printList(self):
+        temp = self.head
+        while temp is not None:
+            print(temp.data)
+            temp = temp.next
+
+    def swap_node(self, key_1, key_2):
+        if key_1 == key_2:
+            return
+        prev_1 = None
+        curr_1 = self.head
+        while curr_1 and curr_1.data != key_1:
+            prev_1 = curr_1
+            curr_1 = curr_1.next
+        prev_2 = None
+        curr_2 = self.head
+        while curr_2 and curr_2.data != key_2:
+            prev_2 = curr_2
+            curr_2 = curr_2.next
+        if not curr_1 or not curr_2:
+            return
+        if prev_1:
+            prev_1.next = curr_2
+        else:
+            self.head = curr_2
+        if prev_2:
+            prev_2.next = curr_1
+        else:
+            self.head = curr_1
+        curr_1.next, curr_2.next = curr_2.next, curr_1.next
+
+
+if __name__ == '__main__':
+    list1 = Linkedlist()
+    list1.head = Node("mon")
+    l2 = Node("tue")
+    l3 = Node("wed")
+    list1.head.next = l2
+    l2.next = l3
+    list1.printList()
+    list1.swap_node("mon", "tue")
+    print(" After swapping nodes: ")
+    list1.printList()