`random.shuffle()` Function Explained

random.shuffle() puts the items in a list into a random order.

It is important to know two things about this function:

It changes the original list
It returns None

This is a common source of beginner mistakes. If you expect a new list to be returned, your code will not work the way you expect.

Quick example

import random

numbers = [1, 2, 3, 4, 5]
random.shuffle(numbers)
print(numbers)

Example output:

[3, 1, 5, 2, 4]

random.shuffle() changes the original list and returns None.

What `random.shuffle()` does

random.shuffle() is used when you want to reorder all items in a list randomly.

Key points:

It shuffles the items in a list into a random order
It works in place, which means it changes the original list
It does not create a new shuffled list
It returns None

If you are new to the random module, see the random module overview.

Basic syntax

Use this form:

import random

random.shuffle(my_list)

Things to remember:

You must import the random module first
You should pass a mutable sequence such as a list
The list is changed directly

What gets changed

When you call random.shuffle(my_list), the original list is modified.

import random

numbers = [1, 2, 3, 4, 5]
random.shuffle(numbers)

print(numbers)

Example output:

[4, 1, 5, 3, 2]

If another variable points to the same list, it will also see the changed order.

import random

numbers = [1, 2, 3, 4, 5]
other_name = numbers

random.shuffle(numbers)

print(numbers)
print(other_name)

Possible output:

[2, 5, 1, 4, 3]
[2, 5, 1, 4, 3]

This happens because both variables refer to the same list object.

If this idea is unfamiliar, it helps to understand mutability in Python.

Simple example

Here is a basic example with a short list:

import random

letters = ["a", "b", "c", "d"]
random.shuffle(letters)

print(letters)

Possible output:

['c', 'a', 'd', 'b']

If you run the program again, the order will usually be different.

That is normal. The purpose of shuffle() is to produce a random ordering.

How to keep the original list unchanged

If you need to keep the original order, make a copy first and shuffle the copy.

You can copy a list with .copy():

import random

original = [1, 2, 3, 4, 5]
shuffled = original.copy()

random.shuffle(shuffled)

print("Original:", original)
print("Shuffled:", shuffled)

Possible output:

Original: [1, 2, 3, 4, 5]
Shuffled: [4, 1, 5, 2, 3]

You can also copy with slicing:

import random

original = [1, 2, 3, 4, 5]
shuffled = original[:]

random.shuffle(shuffled)

print("Original:", original)
print("Shuffled:", shuffled)

This is useful when you need both:

the original list
a random version of the same items

If you want to learn more about copying lists, see list.copy().

Common beginner confusion

`random.shuffle(my_list)` does not return the shuffled list

This is one of the most common mistakes:

import random

numbers = [1, 2, 3, 4, 5]
new_list = random.shuffle(numbers)

print(new_list)
print(numbers)

Output:

None
[2, 4, 1, 5, 3]

Why this happens:

shuffle() changes numbers directly
the return value is None
so new_list becomes None

The correct way is:

import random

numbers = [1, 2, 3, 4, 5]
random.shuffle(numbers)

print(numbers)

You cannot shuffle a tuple or string in place

random.shuffle() is meant for mutable data, usually lists.

This will not work as expected with a tuple:

import random

values = (1, 2, 3, 4)
random.shuffle(values)

A tuple cannot be changed in place.

A string also cannot be shuffled in place because strings are immutable.

If you need to shuffle a tuple or string:

Convert it to a list
Shuffle the list
Convert it back if needed

Example with a tuple:

import random

values = (1, 2, 3, 4)
temp_list = list(values)

random.shuffle(temp_list)

print(temp_list)

Example with a string:

import random

text = "hello"
chars = list(text)

random.shuffle(chars)

shuffled_text = "".join(chars)
print(shuffled_text)

When to use `random.shuffle()` vs `random.choice()`

These two functions solve different problems.

Use random.shuffle() when you want to:

reorder all items in a list
get a random arrangement of the whole list

Use random.choice() when you want to:

pick one random item
leave the original list order unchanged

Example:

import random

numbers = [10, 20, 30, 40]

item = random.choice(numbers)
print("Random item:", item)

random.shuffle(numbers)
print("Shuffled list:", numbers)

Possible output:

Random item: 30
Shuffled list: [20, 40, 10, 30]

If you want to learn that function next, see random.choice() explained.

Common mistakes

Here are the most common problems beginners run into with random.shuffle():

Assigning the result of random.shuffle() to a variable and getting None
Trying to shuffle a tuple or string
Forgetting to import random
Expecting the same shuffled order every time without setting a seed

These quick checks can help when debugging:

import random
print(my_list)
result = random.shuffle(my_list)
print(result)
print(type(my_list))
print(len(my_list))

What these lines help you check:

whether your list contains the values you expect
whether shuffle() returned None
whether your variable is actually a list
whether the list has items in it

If you want a task-focused example, see how to shuffle a list in Python.

FAQ

Does `random.shuffle()` return a new list?

No. It changes the original list and returns None.

Can I use `random.shuffle()` on a tuple?

No. Tuples cannot be changed in place. Convert the tuple to a list first.

Why is my variable `None` after using `random.shuffle()`?

Because shuffle() returns None. It modifies the list directly.

How do I shuffle without changing the original list?

Copy the list first, then shuffle the copy.

random.shuffle() Function Explained

`random.shuffle()` Function Explained