Thanks for that, the difference is a bit more than I hoped but less than I feared =)
At least it confirms (if it was not obvious):

• that both solution are O(n),
• and that a single loop is faster,
• and that we probably need at least 10_000_000 items to compensate the extra time to write the fastest version ;)

which is evidentely the best practice anyway, as a function reason to be is to be called more than once! (But I'm not responsible for most people confusing "best practice" and "shortest solution"…)

Just to needlessly contribute to a 5 year old debate, here are the timings i get:

n=   1000, list_comprehensions: 0.009238 s, for_loop: 0.007677 s
n=  10000, list_comprehensions: 0.100740 s, for_loop: 0.084233 s
n= 100000, list_comprehensions: 1.019162 s, for_loop: 0.908490 s
n=1000000, list_comprehensions: 12.969199 s, for_loop: 11.535525 s

Where n is the list size and
comparing this solution to the solution of Mercy Madmask.

I like seeing the double line break after the import as per PEP 8, rarely see that around

Good Job. This would be the problem we were asked to solve.

very goood

Does it really? I think it reassigns the binding, but doesn't change the referenced object.

I might be wrong, I don't know that much Python.

Oh, yes! You a right!!!
Why did I write True if... else False?...

i feel so sigma!

intersting , thanks anthor

Nice kata to warm up

Yeah, I completely agree with this.

Really cool kata :D