Python: Create a list reflecting the run-length encoding from a list
Python List: Exercise - 75 with Solution
Run-length encoding (RLE) is a form of lossless data compression in which runs of data (sequences in which the same data value occurs in many consecutive data elements) are stored as a single data value and count, rather than as the original run.
Write a Python program to create a list reflecting the run-length encoding from a given list of integers or a given list of characters.
Sample Solution:
Python Code:
from itertools import groupby
def encode_list(s_list):
return [[len(list(group)), key] for key, group in groupby(s_list)]
n_list = [1,1,2,3,4,4.3,5, 1]
print("Original list:")
print(n_list)
print("\nList reflecting the run-length encoding from the said list:")
print(encode_list(n_list))
n_list = 'automatically'
print("\nOriginal String:")
print(n_list)
print("\nList reflecting the run-length encoding from the said string:")
print(encode_list(n_list))
Sample Output:
Original list: [1, 1, 2, 3, 4, 4.3, 5, 1] List reflecting the run-length encoding from the said list: [[2, 1], [1, 2], [1, 3], [1, 4], [1, 4.3], [1, 5], [1, 1]] Original String: automatically List reflecting the run-length encoding from the said string: [[1, 'a'], [1, 'u'], [1, 't'], [1, 'o'], [1, 'm'], [1, 'a'], [1, 't'], [1, 'i'], [1, 'c'], [1, 'a'], [2, 'l'], [1, 'y']]
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Previous: Write a Python program to pack consecutive duplicates of a given list elements into sublists.
Next: Write a Python program to create a list reflecting the modified run-length encoding from a given list of integers or a given list of characters.
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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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