data_structures/linked_list: Adding __str__() function #3960

data_structures/linked_list/__init__.py

@@ -25,6 +25,30 @@ def remove(self):
     def is_empty(self):
         return self.head is None
 
+    def __str__(self):
+        """
+        >>> linked_list = LinkedList()
+        >>> linked_list.add(23)
+        >>> linked_list.add(14)
+        >>> linked_list.add(9)
+        >>> print(linked_list)
+        9 --> 14 --> 23
+        """
+        if not self.is_empty:
+            return "Linked List is empty."
+        else:
+            iterate = self.head
+            item_str = ""
+            item_list = []
+            while iterate:
+                item_list.append(iterate.item)
+                iterate = iterate.next
+
+            item_list = [str(item) for item in item_list]
+            item_str = " --> ".join(item_list)
+
+            return item_str
+
     def __len__(self):
         """
         >>> linked_list = LinkedList()