Python `sorted()` Function Explained

sorted() is a built-in Python function that returns a new list in sorted order.

It is useful when you want to sort values without changing the original data. Unlike list.sort(), sorted() also works with many iterable types, not just lists.

Quick answer

numbers = [3, 1, 2]
result = sorted(numbers)

print(result)      # [1, 2, 3]
print(numbers)     # [3, 1, 2]

sorted() returns a new sorted list and does not change the original object.

What `sorted()` does

sorted() is a built-in Python function.
It returns a new list in sorted order.
It works with many iterable objects, not just lists.
It does not modify the original data.

This means you can use it with lists, tuples, sets, strings, and other iterable values.

Basic syntax

sorted(iterable, key=None, reverse=False)

Parameters

iterable: the values to sort
key: an optional function that decides how items are compared
reverse: set to True to sort in descending order

In many cases, you only need:

sorted(my_values)

Simple example

Here is a basic example with numbers:

numbers = [5, 2, 8, 1]

sorted_numbers = sorted(numbers)

print(sorted_numbers)
print(numbers)

Output:

[1, 2, 5, 8]
[5, 2, 8, 1]

Notice the difference:

sorted_numbers is a new sorted list
numbers stays unchanged

If you want to sort a list in place instead, see how to sort a list in Python.

Sorting different iterable types

sorted() works with more than lists. The result is always a new list.

List

numbers = [3, 1, 2]
print(sorted(numbers))

Output:

[1, 2, 3]

Tuple

values = (3, 1, 2)
print(sorted(values))
print(type(sorted(values)))

Output:

[1, 2, 3]
<class 'list'>

Set

values = {3, 1, 2}
print(sorted(values))

Output:

[1, 2, 3]

String

text = "python"
print(sorted(text))

Output:

['h', 'n', 'o', 'p', 't', 'y']

Dictionary

When you pass a dictionary to sorted(), Python sorts the dictionary keys.

person = {"name": "Ana", "age": 20, "city": "Lima"}
print(sorted(person))

Output:

['age', 'city', 'name']

Using `reverse=True`

Use reverse=True when you want descending order instead of ascending order.

numbers = [3, 1, 2]

print(sorted(numbers))
print(sorted(numbers, reverse=True))

Output:

[1, 2, 3]
[3, 2, 1]

This also works with strings:

words = ["apple", "banana", "cherry"]

print(sorted(words))
print(sorted(words, reverse=True))

Output:

['apple', 'banana', 'cherry']
['cherry', 'banana', 'apple']

Using `key=` for custom sorting

The key= argument lets you control how values are sorted.

Python applies the key function to each item, then sorts based on the result.

A beginner-friendly example is sorting words by length:

words = ["pear", "fig", "banana", "kiwi"]

result = sorted(words, key=len)
print(result)

Output:

['fig', 'pear', 'kiwi', 'banana']

Here, len is used as the key function, so the words are sorted by length.

Another common example is sorting text without caring about uppercase and lowercase letters:

words = ["Banana", "apple", "Cherry"]

result = sorted(words, key=str.lower)
print(result)

Output:

['apple', 'Banana', 'Cherry']

You can learn more about len() in Python len() function explained.

`sorted()` vs `list.sort()`

The main difference is this:

sorted() returns a new list
list.sort() changes the original list

Also:

sorted() works with many iterables
list.sort() only works on lists

Use sorted() when:

you want to keep the original data unchanged
your data is not a list

For a full side-by-side comparison, see Python sorted() vs list.sort() explained.

What can cause errors

A few common problems happen when using sorted().

Mixing values that cannot be compared

This can raise a TypeError:

values = [1, "2", 3]
print(sorted(values))

Python cannot sort integers and strings together in the normal way.

Using the wrong `key` function

If your key function does something invalid for the item type, you may get an error.

Example:

numbers = [10, 2, 30]
print(sorted(numbers, key=len))

This fails because len() does not work on integers.

Expecting the original list to change

This is not a syntax error, but it is a very common beginner mistake:

numbers = [3, 1, 2]
sorted(numbers)

print(numbers)

Output:

[3, 1, 2]

If you do not save the result, the original list stays the same.

Common mistakes

Assuming sorted() changes the original list
Trying to sort mixed types like integers and strings together
Forgetting that sorted() always returns a list
Using key= incorrectly
Calling sort() on a non-list object instead of using sorted()

These quick checks can help while debugging:

print(sorted([3, 1, 2]))
print(type(sorted((3, 1, 2))))
print(sorted(['Banana', 'apple'], key=str.lower))
print(sorted([3, 1, 2], reverse=True))

If Python raises an error because values cannot be compared, that is often a type problem in your data. You may also want to review common list behavior in Python lists explained for beginners.

FAQ

Does `sorted()` change the original list?

No. It returns a new sorted list and leaves the original list unchanged.

What does `sorted()` return?

It always returns a new list, even if you sort a tuple, set, or string.

When should I use `sorted()` instead of `list.sort()`?

Use sorted() when you want a new list or when your data is not a list.

What does `key=` do in `sorted()`?

It tells Python what value to use when comparing each item during sorting.

Why does `sorted()` give a `TypeError`?

Usually because the items cannot be compared directly, such as mixing strings and integers.

Python sorted() Function Explained

Python `sorted()` Function Explained