Python sorted()

The Python sorted() function is a built-in function that returns a new sorted list from the items of any iterable. It accepts three parameters: iterable (the sequence to sort), an optional key function that extracts a comparison key from each element, and an optional reverse boolean that sorts in descending order when set to True. The function always returns a new list, leaving the original iterable unchanged, which makes it safe to use without worrying about mutating your source data. Unlike the list.sort() method, sorted() works on any iterable including tuples, sets, dictionaries, and generators. This makes it invaluable for tasks like ranking search results, ordering database records by a specific field, or alphabetizing user input. The key parameter is particularly powerful, allowing you to sort complex objects by any attribute or computed value. It works well with min() and max() for finding extreme values in collections.

What does sorted() return?

The sorted() function always returns a new list containing all items from the input iterable arranged in ascending order by default, or descending order if reverse=True.

When should you use sorted()?

Use sorted() when you need a sorted copy of any iterable without modifying the original, or when sorting non-list iterables like tuples, sets, or dictionary keys.

The syntax of sorted() is:

sorted(iterable, key, reverse)

sorted() Parameters

The sorted() function takes three parameters as argument:

• iterable - an iterable object like string, list,set, etc.
• key (Optional) - A Function to execute to decide the order. Default is None.
• reverse (Optional) -

Let see an example of the sorted() function.

Example 1: How to use sorted() function in python?

a = (2, 5, 3)
x = sorted(a)
print(x)

Output:

[2, 3, 5]

Example 2: sorted() function with python string.

a = ("h", "b", "a", "c", "f", "d", "e", "g")
x = sorted(a)
print(x)

Output:

['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']

Common Use Cases

A common use case for sorted() is sorting a list of dictionaries by a specific key, such as ordering a list of products by price using sorted(products, key=lambda x: x['price']). Another practical scenario is sorting user-generated content alphabetically for display, such as sorting names in a contact list or tags on a blog. It is also frequently used to sort the results of filter() or map() operations in data processing pipelines where the output needs to be presented in a deterministic order.

More Examples

Sorting with a key function

words = ["banana", "kiwi", "apple", "fig"]
print(sorted(words, key=len))        # ['fig', 'kiwi', 'apple', 'banana']
print(sorted(words, key=len, reverse=True))

The key parameter lets you sort by any derived value — length, a dictionary field, or a computed score.

Sorting a list of dictionaries

people = [
    {"name": "Alice", "age": 30},
    {"name": "Bob", "age": 25},
    {"name": "Carol", "age": 35},
]
by_age = sorted(people, key=lambda p: p["age"])
print([p["name"] for p in by_age])   # ['Bob', 'Alice', 'Carol']

sorted() vs list.sort()

Feature	sorted()	list.sort()
Returns	A new list	None
Works on	Any iterable	Lists only
Original	Unchanged	Modified in place

Use sorted() when you need a new sorted sequence and want to keep the original; use list.sort() to sort a list in place.

Real-World Use Cases

• Ranking — ordering scores, prices, or timestamps.
• Display — alphabetising names or sorting search results.
• Pre-processing — sorting before binary search or grouping.

Common Mistakes

• Expecting in-place sorting — sorted() returns a new list; the original is untouched.
• Comparing incompatible types — sorting a mix of strings and numbers raises TypeError.
• Overusing reverse with a key — you can often invert the key instead for clarity.

FAQ

Q: Is sorted() stable? Yes — equal elements keep their original relative order, which is useful for multi-key sorting.

Q: Can I sort in descending order? Yes — pass reverse=True, or negate a numeric key.

Conclusion

sorted() returns a new sorted list from any iterable, leaving the source unchanged. With its key and reverse parameters it can express almost any ordering you need, from simple alphabetical sorts to complex multi-field rankings. Because it is stable and works on any iterable, sorted() is one of the most versatile built-ins in Python.