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Python 2 in Python 3!

A post about how this community's banner used the python 2 print syntax - print "Hello World" - made me question, can we print a hello world message in Python 3 without using parentheses?

It turned out to be sort of a fun challenge, I've found 3 different approaches that work. I'd be interested to see what you come up with! (it seems I can't put spoilers in Lemmy, so I won't share my solutions yet in case y'all want to have a go).

Edit: Posted my solutions in the comments

View original on programming.dev
20
Comments12
Paboreply
feddit.nl

Same on Jerboa. Though given the apps' fast development progress we probably won't have to wait too long :)

5
McChengreply
lemmy.fmhy.ml

But then you still need to use parentheses to decode it

3
jormaigreply
programming.dev

Ah sorry I meant for the spoiler. He could base64 the solution given that he doesn't know how to do spoilers on lemmy

2
qwopreply
programming.dev

Ah true that would have worked, figured since spoilers don't work on most apps I might as well just post them.

1
McCheng
lemmy.fmhy.ml

Gave some thoughts but couldn't find any. I need the solutions

2
qwopreply
programming.dev

Alright, here are my solutions :)

  1. Import Easter egg
import __hello__

Not the most technically interesting, but a fun Easter egg!

  1. Class decorators
@print
@lambda _: "Hello World"
class Foo: 
    ...

Decorators are another way of calling a function, so can be abused to solve this task. You need to decorate a class rather than a function though, since a function definition requires parentheses!

  1. Dunder methods
class Printer:
    __class_getitem__ = print

Printer["Hello World"]

There might be some other Dunder methods you can use to do this, although it's sort of difficult since most (e.g. __add__) only describe behaviour on the instance of the class.

  1. More dunder methods
from _sitebuiltins import Quitter
Quitter.__add__ = print
exit + "Hello World"

Writing number 3 made me realise I just needed to find a class that already had an instance and change that. I'm sure there are many other cases of this, but here's one!

7
McChengreply
lemmy.fmhy.ml

Very interesting solutions. I was in the direction of using dunder methods but could not figure out how. Haven't heard of the __class_getitem__. The second solution is especially inspiring.

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