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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:

Flowchart: Randomize the order of the values of an list.

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Python Code Editor:

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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.

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Python: Tips of the Day

Floor Division:

When we speak of division we normally mean (/) float division operator, this will give a precise result in float format with decimals.

For a rounded integer result there is (//) floor division operator in Python. Floor division will only give integer results that are round numbers.

print(1000 // 300)
print(1000 / 300)

Output:

3
3.3333333333333335