[Term Entry] Python deque : clear() #7753

content/python/concepts/deque/terms/clear/clear.md

@@ -0,0 +1,76 @@
+---
+Title: 'clear()'
+Description: 'Removes all elements from the deque, leaving it empty.'
+Subjects:
+  - 'Computer Science'
+  - 'Data Science'
+Tags:
+  - 'Algorithms'
+  - 'Collections'
+  - 'Data Structures'
+  - 'Deques'
+CatalogContent:
+  - 'learn-python-3'
+  - 'paths/computer-science'
+---
+
+The **`clear()`** method in Python’s `collections.deque` class removes all elements from the deque, leaving it empty. It’s useful when the contents of the deque need to be cleared without deleting the object itself.
+
+The method modifies the deque in place and returns `None`. Its time complexity is O(n) since it removes elements one by one.
+
+## Syntax
+
+```pseudo
+deque.clear()
+```
+
+**Parameters:**
+
+- `None`: This method does not take any parameters as it simply resets the deque to empty
+
+**Return value:**
+
+The return value of `clear()` should be a check to determine if the deque is empty. This can be done using an 'if' statement with a return value of 'true' when checked if empty. Or simply a print statement to output the length of the deque.
+
+## Example 1: Clearing all elements from a deque
+
+In this example, the `clear()` method removes every element from the deque, and an `if` statement checks whether it is empty afterward:
+
+```py
+from collections import deque
+
+# Create a deque
+cars = deque(["toyota", "suzuki", "honda"])
+print(f"Initial deque is as follows: {cars}")
+
+# Clearing the deque
+cars.clear()
+
+# If statement to check if the deque has been sucessfully cleared
+if not cars:
+  print("the deque is empty")
+```
+
+The output of this code is:
+
+```shell
+Initial deque: deque(['Toyota', 'Suzuki', 'Honda'])
+The deque is empty.
+```
+
+## Codebyte Example: Clearing completed tasks
+
+In this example, a deque keeps track of recent tasks in a to-do list. After all tasks are completed, the `clear()` method is used to empty the deque and prepare it for new tasks:
+
+```codebyte/python
+from collections import deque
+
+# Create a deque of completed tasks
+completed_tasks = deque(["Write report", "Send emails", "Backup files"])
+print(f"Completed tasks: {completed_tasks}")
+
+# Clear all tasks to reuse the deque for a new session
+completed_tasks.clear()
+
+print(f"Tasks after clearing: {completed_tasks}")
+```