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
Python Collections: Exercise-7 with Solution
Write a Python program to 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.
Sample Solution:
Python Code:
import collections
# Create a deque
deque_colors = collections.deque(["Red","Green","White"])
print(deque_colors)
# Append to the left
print("\nAdding to the left: ")
deque_colors.appendleft("Pink")
print(deque_colors)
# Append to the right
print("\nAdding to the right: ")
deque_colors.append("Orange")
print(deque_colors)
# Remove from the right
print("\nRemoving from the right: ")
deque_colors.pop()
print(deque_colors)
# Remove from the left
print("\nRemoving from the left: ")
deque_colors.popleft()
print(deque_colors)
# Reverse the dequeue
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'])
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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.
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Python: Tips of the Day
Find current directory and file's directory:
To get the full path to the directory a Python file is contained in, write this in that file:
import os dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)
To get the current working directory use
import os cwd = os.getcwd()
Documentation references for the modules, constants and functions used above:
- The os and os.path modules.
- The __file__ constant
- os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
- os.path.dirname(path) (returns "the directory name of pathname path")
- os.getcwd() (returns "a string representing the current working directory")
- os.chdir(path) ("change the current working directory to path")
Ref: https://bit.ly/3fy0R6m
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