﻿ Python: Randomize the order of the values of an list - w3resource

# 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 a 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:

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## Python: Tips of the Day

Returns True if the provided function returns True for every element in the list, False otherwise:

Example:

```def tips_every(lst, fn=lambda x: x):
return all(map(fn, lst))

print(tips_every([2, 4, 3], lambda x: x > 1))
print(tips_every([1, 2, 3]))
```

Output:

```True
True
```