Table of Contents
The reversed() function returns the reversed iterator of the given sequence.
The syntax of reversed()
is:
reversed(seq)
1. reversed() Parameters
The reversed()
function takes a single parameter:
- seq – the sequence to be reversed
A sequence is an object that supports sequence protocols: __len__()
and __getitem__()
methods. For example, tuple, string, list, range, etc.
We can also use reversed()
in any object that implements __reverse__()
.
2. Return value from reversed()
The reversed()
function returns an iterator that accesses the given sequence in the reverse order.
3. Example 1: Using reveresed() in string, tuple, list, and range
# for string seq_string = 'Python' print(list(reversed(seq_string))) # for tuple seq_tuple = ('P', 'y', 't', 'h', 'o', 'n') print(list(reversed(seq_tuple))) # for range seq_range = range(5, 9) print(list(reversed(seq_range))) # for list seq_list = [1, 2, 4, 3, 5] print(list(reversed(seq_list)))
Output
['n', 'o', 'h', 't', 'y', 'P'] ['n', 'o', 'h', 't', 'y', 'P'] [8, 7, 6, 5] [5, 3, 4, 2, 1]
In our example, we have converted the iterators returned by reversed()
to list using the list()
function.
4. Example 2: reversed() in custom objects
class Vowels: vowels = ['a', 'e', 'i', 'o', 'u'] def __reversed__(self): return reversed(self.vowels) v = Vowels() print(list(reversed(v)))
Output
['u', 'o', 'i', 'e', 'a']
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