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Python: Rotate a given list by specified number of items to the right or left direction

Python List: Exercise - 109 with Solution

Write a Python program to rotate a given list by specified number of items to the right or left direction.

Sample Solution:

Python Code:

nums1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print("original List:")
print(nums1)
print("\nRotate the said list in left direction by 4:")
result = nums1[3:] + nums1[:4]
print(result)
print("\nRotate the said list in left direction by 2:")
result = nums1[2:] + nums1[:2]
print(result)
print("\nRotate the said list in Right direction by 4:")
result = nums1[-3:] + nums1[:-4]
print(result)
print("\nRotate the said list in Right direction by 2:")
result = nums1[-2:] + nums1[:-2]
print(result)

Sample Output: 

original List:
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Rotate the said list in left direction by 4:
[4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4]

Rotate the said list in left direction by 2:
[3, 4, 5, 6, 7, 8, 9, 10, 1, 2]

Rotate the said list in Right direction by 4:
[8, 9, 10, 1, 2, 3, 4, 5, 6]

Rotate the said list in Right direction by 2:
[9, 10, 1, 2, 3, 4, 5, 6, 7, 8]

Flowchart:

Flowchart: Rotate a given list by specified number of items to the right or left direction.

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Python Code Editor:

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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