please do not post solutions in the discourse, otherwise anyone can see it without the spoiler flag. I have added the flag to your comment.

What if needle does not exist in haystack ?!

saving a line break, does it really make the code faster? xD

Wow, didn't know you could define a function with an output in one line.

Probably the best solution

The one example you showed using f string doesn't seems to work for me.

Update : sorry I should have put double quotation "needle" instead of 'needle'

I do the exact same thing then see someone being cleverer as always. I learn so much from this website! Also lambda would be even shorter

Actually it was the same for me but looking at other peoples solutions actually improved my future solutions... this website is one of the most helpful things ive used

its the pythonic way to do it

its sometimes more readable

Says the guy who did it in one line

Because it looks like we are pros I think =))

Why do people always so depserately try to do it in 1 line?

I assume it has something to do with it being simpler, however realisticly I think it makes it harder to read, not sure, probably also something to do with the single line looking more efficient at a glance, despite being the same output in the same amount of code as lower ones. Just a guess though.