Python reversed() Method
Python reversed() method returns an iterator that accesses the given sequence in the reverse order.
Example:
Python3
# creating a list cars = [ "nano" , "swift" , "bolero" , "BMW" ] # reversing the list reversed_cars = list ( reversed (cars)) #printing the list print (reversed_cars) |
['BMW', 'bolero', 'swift', 'nano']
Python reversed() Method Syntax
reversed(sequence)
Parameter :
- sequence : Sequence to be reversed.
Return : Returns an iterator that accesses the given sequence in the reverse order.
How to use reversed function in Python?
reversed() method is very easy to use and it returns an iterator that accesses the list in reverse order. Let’s understand it better with an example.
Example:
In the given example, we are reversing elements of the list with reversed() function in Python.
Python3
my_list = [ "apple" , "banana" , "cherry" , "date" ] reversed_list = list ( reversed (my_list)) print (reversed_list) |
['date', 'cherry', 'banana', 'apple']
More Python reversed() Method Examples
Let’s see some of the other common scenarios for reversed() method.
1. Python reversed() with Built-In Sequence Objects
In the given example we have used reversed() with tuple and range. When using reversed with these objects we need to use the list() method to convert the output from reversed() to list.
Python3
# For tuple seqTuple = ( 'g' , 'e' , 'e' , 'k' , 's' ) print ( list ( reversed (seqTuple))) # For range seqRange = range ( 1 , 5 ) print ( list ( reversed (seqRange))) |
['s', 'k', 'e', 'e', 'g'] [4, 3, 2, 1]
2. Python reversed() with for loop in Python
In this example, we are using reversed() function to show it’s working with Python loops.
Python3
# Create a string str = "Reversed in Python" # Reverse the string and print its characters in reverse order for char in reversed ( str ): print (char, end = "") |
nohtyP ni desreveR
Output
nohtyP ni desreveR
3. Python reversed() in Python with custom objects
In this example, we are creating a class gfg which includes a list of vowels we are using the reversed function to reverse the vowels.
Python3
class gfg: vowels = [ 'a' , 'e' , 'i' , 'o' , 'u' ] # Function to reverse the list def __reversed__( self ): return reversed ( self .vowels) # Main Function if __name__ = = '__main__' : obj = gfg() print ( list ( reversed (obj))) |
['u', 'o', 'i', 'e', 'a']
4. Python reversed() method with List
In this example, we are reversing a list of vowels with the reversed function in Python.
Python3
vowels = [ 'a' , 'e' , 'i' , 'o' , 'u' ] print ( list ( reversed (vowels))) |
['u', 'o', 'i', 'e', 'a']
5. Python reversed() method with string
In this example, we are reversing a string with the reversed function in Python.
Python3
str = "w3wiki" print ( list ( reversed ( str ))) |
['s', 'k', 'e', 'e', 'g', 'r', 'o', 'f', 's', 'k', 'e', 'e', 'G']
Exception in reversed() function
In this example, we are showing the exception in reversed() function.
Python3
# Create a list lst = [ 1 , 2 , 3 ] # Reverse the list using the `reversed` function reversed_lst = reversed (lst) # Print the reversed elements one by one using the `next` function print ( next (reversed_lst)) print ( next (reversed_lst)) print ( next (reversed_lst)) # Attempting to print the next element will raise a StopIteration exception print ( next (reversed_lst)) # Exception |
Output
3
2
1
StopIteration
print(next(my_list_rev)) # Exception
Line 13 in <module> (Solution.py)
We have covered the definition, syntax and different uses of reversed() method in Python. Python reversed() function is very important function to access sequence from the end.
reversed() method can be used to reverse a set, list,tuple, etc in Python.
Hope this article helped you in your Python journey!