Python sorted() Function

The sorted() function in Python is used to sort elements of any iterable (like a list, tuple, or string) and return a new sorted list. It does not modify the original data.

Syntax

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

Parameters:

• iterable – The sequence to be sorted (like list, tuple, set, dictionary keys, string, etc.)
• key (optional) – A function to customize sorting logic
• reverse (optional) – If True, sorts in descending order

Returns:

• A new sorted list.

Example 1: Sorting a List

numbers = [4, 2, 9, 1]
print(sorted(numbers))

[1, 2, 4, 9]

Example 2: Sorting in Reverse Order

numbers = [4, 2, 9, 1]
print(sorted(numbers, reverse=True))

[9, 4, 2, 1]

Example 3: Sorting Strings Alphabetically

fruits = ["banana", "apple", "cherry"]
print(sorted(fruits))

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

Example 4: Sorting with a Key Function

# Sort by length of strings
words = ["apple", "banana", "fig", "date"]
print(sorted(words, key=len))

['fig', 'date', 'apple', 'banana']

Example 5: Sorting Tuples by Second Element

pairs = [(1, 3), (2, 2), (4, 1)]
print(sorted(pairs, key=lambda x: x[1]))

[(4, 1), (2, 2), (1, 3)]

Use Cases

• Alphabetical sorting of names or words
• Sorting numbers for comparisons
• Custom sorting using key, like sorting objects by attributes
• Sorting dictionary keys or values

Common Mistakes

• Expecting sorted() to change the original list – it returns a new one
• For descending order, forgetting to use reverse=True
• Passing non-iterable values like integers

Interview Tip

Use sorted() with custom key functions to solve problems like sorting students by grades, or sorting tuples by second item.

Summary

• sorted() returns a new sorted list from any iterable
• Supports key for custom sort logic
• Set reverse=True for descending order

Practice Problem

Write a program that reads 5 space-separated numbers and prints them in descending order.

nums = list(map(int, input("Enter 5 numbers: ").split()))
sorted_nums = sorted(nums, reverse=True)
print("Sorted descending:", sorted_nums)