'Reverse a List in Python' Tutorial: Three Methods & How-to Demos

In this Python tutorial video you'll see how to reverse a list in Python. There are 3 common implementations for a Python reverse list algorithm and we'll do a deep dive on all of them. Here's what we'll cover with overviews and hands on REPL demos:

2. Using a list slicing "trick" to create a reversed copy of a Python list. You can use Python's list slicing syntax to create a reversed copy of a list: `my_list[::-1]`. This works well, however it is slightly arcane and therefore not very Pythonic, in my opinion.

3. Using Python's built-in "reversed()" function to create a reverse iterator that we can then turn into a proper list object. This is a clean solution that uses some advanced Python features like iterators—but it's also very readable due to the naming of the "reversed" function. This is a great option if you're looking to reverse a for loop and you don't need a full copy of the original list.

Note that there are other approaches like implementing list reversal from scratch or reversing a list using a recursive algorithm that are common interview questions but not very good solutions for Python programming in the "real world".

Watch the full video for details and hands-on demos for each approach. At the end of the video you'll see my final verdict on which list reversal approach I recommend and why.

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[cr]

Best I have seen so far. Thanks for breaking this down

[sibusisoharvey]

You are amazing, eloquent and have good communication skills, Thank you

[zomaarwat]

The reversed iterator however is sensitive to modify/delete of an item in the list while iterating.

>>> mylist = [1, 2, 3, 4, 5]
>>> rev = reversed(mylist)
>>> next(rev)
5
>>> next(rev)
4
>>> mylist.remove(3)
>>> next(rev)
4
>>> next(rev)
2

[supermalavox]

I don't know if it's because I am crazy or because a sighted person's brain works differently from a blind person's one, but I liked the second method because, considering that everything in python is an object, I imagine myself touching the list items as if they were small boxes. So, knowing that the :: takes me to the end of the list (or of a string), since the first and second values are omitted, I am in the end of the list or string, so the -1 that comes after it is kind of intuitive.
But it was fun to learn the various methods to reverse a list! Thanks!

P.S.: There is even a free screen reader for Windows programmed in Python, so it helps us a lot. I guess our biggest problem is with indentation, since they are not spoken unless we spell the code!

[teoguso]

It's funny. I think list slicing is a very obvious syntax for any user of the numpy/scipy stack. But I get it when you say it's not very pythonic. Was it promoted by some former Fortran users back in the day? Anyway, I think this helps me and others to understand and bridge the gap between science and software development. Keep up he good work!

[labtest]

Nice Explanation.
It appears, the reversed function works a bit differently on a string than on a list. Could you please explain how that happens?

[liladharlingayat]

Very nice explanatiin.
Will you please tell me How to creat a REST API with any framework (Flask, cherrypy, Django, etc., ). Create a simple PY calculator that is accessible via GET and POST method.

[aishwarysaxena]

hope this trik also help someone of list comprensation

lis = [item for item in reversed(list1)]
print(lis)

[karna]

Bro can you explain why do we use -1 in reverse

[Gentlemanek]

How about this :
ls = [1, 2, 3, 4, 5]
ls2 = []
for i in ls:
ls2.insert(0, i)

print(ls2)

[leonardohernandez]

method #3 seems more complicated for a beginner

[swethamk]

How to get a list input.. Like this [1, 2, 3, 4] as an input and print it like [4, 3, 2, 1]

[jayprakashpatel]

for loop se kar ke dikhaeye without function ka

[wintersilence]

That thing in the interpreter... the one with a docstring... bepython? beepython? beerpython?

[Juanbaez_]

I hate these people never link the playlist.