Python: Get a list with n elements removed from the left, right

Last update on May 28 2022 13:48:53 (UTC/GMT +8 hours)

Python List: Exercise - 268 with Solution

Write a Python program to get a list with n elements removed from the left, right.

Removed from the left:

Use slice notation to remove the specified number of elements from the left.
Omit the last argument, n, to use a default value of 1.

Removed from the right:

Returns a list with n elements removed from the right.

Use slice notation to remove the specified number of elements from the right.
Omit the last argument, n, to use a default value of 1.

Sample Solution:

Python Code:

def drop_left_right(a, n = 1):
  return a[n:], a[:-n] 
nums = [1, 2, 3]
print("Original list elements:")
print(nums)
result = drop_left_right(nums)
print("Remove 1 element from left of the said list:")
print(result[0])
print("Remove 1 element from right of the said list:")
print(result[1])
nums = [1, 2, 3, 4]
print("\nOriginal list elements:")
print(nums)
result = drop_left_right(nums,2)
print("Remove 2 elements from left of the said list:")
print(result[0])
print("Remove 2 elements from right of the said list:")
print(result[1])
nums = [1, 2, 3, 4, 5, 6]
print("\nOriginal list elements:")
print(nums)
result = drop_left_right(nums)
print("Remove 7 elements from left of the said list:")
print(result[0])
print("Remove 7 elements from right of the said list:")
print(result[1])

Sample Output:

Original list elements:
[1, 2, 3]
Remove 1 element from left of the said list:
[2, 3]
Remove 1 element from right of the said list:
[1, 2]

Original list elements:
[1, 2, 3, 4]
Remove 2 elements from left of the said list:
[3, 4]
Remove 2 elements from right of the said list:
[1, 2]

Original list elements:
[1, 2, 3, 4, 5, 6]
Remove 7 elements from left of the said list:
[2, 3, 4, 5, 6]
Remove 7 elements from right of the said list:
[1, 2, 3, 4, 5]

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Next: Write a Python program to get the every nth element in a given list.

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