.len doesn't work on a list (because it might mislead you about the efficiency of the operation if it did exist), so it's better to use iterators - so then you can change the underlying type without changing your code.
replyBut then, saying while "let Some(item) = iter.next()" everytime is tedious, so they give you .iter() - for any type that is efficiently iterable.
Nothing stopping you using a manual loop that you need to update if you change the container type.
items.filter(|(i)| cond(i)).map(Pointer::idx).collect()
items is already an iteratible so you can do direct .filter on it as well
tl;dr if the code looks ugly you're probably not taking advantage of a language feature that allows it to look pretty.
This is in fact more readable, thank you.
replyI still don’t know that I find it more intuitive or readable than the simple loop, but it’s much less awful than before.
I am sure there's a way to filter directly on cond variable and collect isn't needed most of the time since iterators are way more useful in general (unless you want to print that data)
reply items.filter(cond).map(Pointer::idx)