Why Does Python\'s `random.shuffle()` Return None?

Why Random.shuffle() Returns None

Python's random.shuffle() function may appear to return None in certain situations. Understanding the purpose of random.shuffle() is crucial to resolving this issue.

random.shuffle() is used to shuffle a list in place. Unlike many functions that return a modified copy of a structure, random.shuffle() modifies the original list without creating a new one. Therefore, when calling random.shuffle(x), x itself is shuffled, and None is returned as the function does not explicitly generate a new list.

Getting the Shuffled Value

To obtain the shuffled value, simply print or access the original list after calling random.shuffle().

import random
x = ['foo', 'bar', 'black', 'sheep']
random.shuffle(x)
print(x)  # Prints the shuffled list

Creating a New Shuffled List

If you want to create a new randomly shuffled list without modifying the original one, use either random.sample() or sorted().

Using random.sample():

import random
x = ['foo', 'bar', 'black', 'sheep']
shuffled_list = random.sample(x, len(x))

Using sorted():

import random
x = ['foo', 'bar', 'black', 'sheep']
shuffled_list = sorted(x, key=lambda k: random.random())

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