Working With Iterables

Sorting and Reversing Sequences

Learn how to use Python's built-in sorted() and reversed() functions to create sorted and reversed copies of any iterable.

Python's built-in sorted() function takes any iterable and returns a new sorted list — without touching the original.

Here, we sort a list of numbers:

nums = [3, 1, 4, 1, 5, 9, 2, 6]
sorted_nums = sorted(nums)
print(sorted_nums)

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Output

The basic syntax of sorted():

sorted(iterable)
sorted(iterable, reverse=True)

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sorted() works on any iterable, including strings and tuples:

words = ['banana', 'apple', 'cherry']
print(sorted(words))

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Output

nums = [5, 2, 8, 1]
print(sorted(nums))

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Pass reverse=True to sort in descending order.

Sorting the same list in descending order:

nums = [3, 1, 4, 1, 5]
print(sorted(nums, reverse=True))

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Output

words = ['banana', 'apple', 'cherry']
print(sorted(words, reverse=True))

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Importantly, sorted() never modifies the original iterable. It always returns a brand-new list.

The original list stays unchanged:

nums = [3, 1, 4]
sorted_nums = sorted(nums)
print(nums)
print(sorted_nums)

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Output

nums = [5, 2, 8]
result = sorted(nums)
print(nums)

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The reversed() function returns an iterator that yields items from a sequence in reverse order.

Wrap reversed() in list() to see the result:

nums = [1, 2, 3, 4, 5]
rev = list(reversed(nums))
print(rev)

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Output

You can also iterate over reversed() directly in a for-loop:

for n in reversed([10, 20, 30]):
	print(n)

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Output

nums = [1, 2, 3]
print(list(reversed(nums)))

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nums = [1, 2, 3, 4, 5]
result = sorted(nums, reverse=True)
print(result[0])

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words = ['kiwi', 'apple', 'mango']
result = sorted(words)
print(result[-1])

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

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