Python reversed()

seq_string = 'Python'

# reverse of a string
print(list(reversed(seq_string)))

# Output: ['n', 'o', 'h', 't', 'y', 'P']

reversed() Syntax

The syntax of reversed() is:

reversed(sequence_object)

reversed() Parameter

The reversed() method takes a single parameter:

• sequence_object - an indexable object to be reversed (can be a tuple, string, list, range, etc.)

Note: Since we can't index objects such as a set and a dictionary, they are not considered sequence objects.

reversed() Return Value

The reversed() method returns:

• a reversed list of items present in a sequence object

Example 1: Python reversed() with Built-In Sequence Objects

seq_tuple = ('P', 'y', 't', 'h', 'o', 'n')

# reverse of a tuple object
print(list(reversed(seq_tuple)))

seq_range = range(5, 9)

# reverse of a range
print(list(reversed(seq_range)))

seq_list = [1, 2, 4, 3, 5]

# reverse of a list
print(list(reversed(seq_list)))

Output

['n', 'o', 'h', 't', 'y', 'P']
[8, 7, 6, 5]
[5, 3, 4, 2, 1]

In the above example, we have used the reversed() method with objects like tuple, range and a list.

When using the reversed() method with these objects, we need to use the list() method to convert the output from the reversed() method to a list.

Example 2: reversed() with Custom Objects

class Vowels:
    vowels = ['a', 'e', 'i', 'o', 'u']

    def __reversed__(self):
        return reversed(self.vowels)

v = Vowels()

# reverse a custom object v
print(list(reversed(v)))

Output

['u', 'o', 'i', 'e', 'a']

In the above example, we have used the reversed() method with a custom object v of the Vowels class.

Here, the method returns the reverse order of the sequence in the vowels list.

Recommended Readings:

• Python str()
• Python iter()