Python: Randomize the order of the values of an list

Python List: Exercise - 221 with Solution

Write a Python program to randomize the order of the values of an list, returning a new list.

• Uses the Fisher-Yates algorithm to reorder the elements of the list.
• random.shuffle provides similar functionality to this snippet.

From Wikipedia,
The Fisher–Yates shuffle is an algorithm for generating a random permutation of a finite sequence—in plain terms, the algorithm shuffles the sequence. The algorithm effectively puts all the elements into a hat; it continually determines the next element by randomly drawing an element from the hat until no elements remain. The algorithm produces an unbiased permutation: every permutation is equally likely. The modern version of the algorithm is efficient: it takes time proportional to the number of items being shuffled and shuffles them in place.

Sample Solution:

Python Code:

from copy import deepcopy
from random import randint
def shuffle_list(lst):
  temp_lst = deepcopy(lst)
  m = len(temp_lst)
  while (m):
    m -= 1
    i = randint(0, m)
    temp_lst[m], temp_lst[i] = temp_lst[i], temp_lst[m]
  return temp_lst
nums = [1, 2, 3, 4, 5, 6]
print("Original list: ",nums)
print("\nShuffle the elements of the said list:")
print(shuffle_list(nums))

Sample Output:

Original list:  [1, 2, 3, 4, 5, 6]

Shuffle the elements of the said list:
[3, 2, 4, 1, 6, 5]

Flowchart:

Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:

Python Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Write a Python program to map the values of a list to a dictionary using a function, where the key-value pairs consist of the original value as the key and the result of the function as the value.
Next: Write a Python program to get the difference between two given lists, after applying the provided function to each list element of both.