How to Use Sorted Function in Python: Syntax and Examples

Use the sorted() function in Python to return a new sorted list from any iterable. You can sort in ascending order by default or use the reverse=True argument to sort in descending order. The key argument lets you customize sorting based on a function.

Syntax

The sorted() function syntax is:

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

iterable: any sequence or collection to sort (like list, tuple, string).

key: a function that extracts a comparison key from each element (optional).

reverse: if True, sorts in descending order (optional).

python

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

Example

This example shows sorting a list of numbers in ascending and descending order, and sorting strings by their length using the key argument.

python

numbers = [5, 2, 9, 1]
sorted_numbers = sorted(numbers)
sorted_numbers_desc = sorted(numbers, reverse=True)
words = ['apple', 'banana', 'cherry', 'date']
sorted_by_length = sorted(words, key=len)

print('Ascending:', sorted_numbers)
print('Descending:', sorted_numbers_desc)
print('By length:', sorted_by_length)

Output

Ascending: [1, 2, 5, 9]
Descending: [9, 5, 2, 1]
By length: ['date', 'apple', 'banana', 'cherry']

Common Pitfalls

Common mistakes include:

• Trying to sort a list in place using sorted() instead of list.sort(). sorted() returns a new list and does not change the original.
• Not using the key argument correctly, which can cause unexpected order.
• Forgetting that sorted() works on any iterable, not just lists.

python

numbers = [3, 1, 4]
# Wrong: expecting sorted() to change original list
sorted(numbers)
print(numbers)  # Output: [3, 1, 4]

# Right: assign sorted result or use list.sort()
sorted_list = sorted(numbers)
print(sorted_list)  # Output: [1, 3, 4]

Output

[3, 1, 4]
[1, 3, 4]

Quick Reference

Parameter	Description	Default
iterable	The sequence or collection to sort	Required
key	Function to extract sorting key from each element	None
reverse	Sort in descending order if True	False

Key Takeaways

Use sorted() to get a new sorted list from any iterable without changing the original.

Use the key parameter to customize sorting based on a function like len or a lambda.

Set reverse=True to sort in descending order.

Remember sorted() returns a new list; use list.sort() to sort in place.

sorted() works on lists, tuples, strings, and other iterables.