Python: Create a deque and append few elements to the left and right, then remove some elements from the left, right sides and reverse the deque

Last update on April 21 2025 12:56:04 (UTC/GMT +8 hours)

7. Create a Deque and Append/Remove Elements, Then Reverse It

Write a Python program to create a deque and append a few elements to the left and right. Next, remove some elements from the left and right sides and reverse the deque.

Sample Solution:

Python Code:

# Import the collections module to use the deque data structure
import collections

# Create a deque named 'deque_colors' with initial elements "Red", "Green", and "White"
deque_colors = collections.deque(["Red", "Green", "White"])

# Print the original deque
print(deque_colors)

# Append "Pink" to the left of the deque
print("\nAdding to the left: ")
deque_colors.appendleft("Pink")
print(deque_colors)

# Append "Orange" to the right of the deque
print("\nAdding to the right: ")
deque_colors.append("Orange")
print(deque_colors)

# Remove and print the element from the right of the deque
print("\nRemoving from the right: ")
deque_colors.pop()
print(deque_colors)

# Remove and print the element from the left of the deque
print("\nRemoving from the left: ")
deque_colors.popleft()
print(deque_colors)

# Reverse the order of elements in the deque
print("\nReversing the deque: ")
deque_colors.reverse()
print(deque_colors)

Sample Output:

deque(['Red', 'Green', 'White'])

Adding to the left: 
deque(['Pink', 'Red', 'Green', 'White'])

Adding to the right: 
deque(['Pink', 'Red', 'Green', 'White', 'Orange'])

Removing from the right: 
deque(['Pink', 'Red', 'Green', 'White'])

Removing from the left: 
deque(['Red', 'Green', 'White'])

Reversing the deque: 
deque(['White', 'Green', 'Red'])

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to create a deque, add elements to both ends, and then remove elements from both sides before finally reversing the deque.
Write a Python program to simulate a queue with a deque where items are appended to the right and removed from the left, then reverse the queue.
Write a Python program to implement a function that performs a series of appendleft() and append() operations on a deque and then returns its reversed form.
Write a Python program to build a deque from user input, modify it with a series of insertions and deletions, and then print it in reverse order.

Go to:

Previous: Write a Python program that accepts number of subjects, subject names and marks. Input number of subjects and then subject name, marks separated by a space in next line. Print subject name and marks in order of its first occurrence.
Next: Write a Python program to create a deque from an existing iterable object.

Python Code Editor: