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kotlinlang

I have `method(input:Set&lt;X&gt;):Set&lt;X&gt;`, which wants to transform each element of the (small) set, seemingly a natural fit with `.map { }`, _but_, the transformation can produce invalid individual values, and if that occurs the method's result will be `emptySet()`. In other words, under some conditions i want to short-circuit the mapping and just return the empty set. I am wondering if there is some clever stream-ish/sequence-ish way to accomplish this, or should I just go with a for-in and a result accumulator?

`map` is inline, so you can return from the outer function inside its lambda. 

So, something like `.map { x = transform; if(x.isbad) return emptySet(); x }` will work?

The easiest way to find out is to try it :wink: But yes, as long as your collection is not a `Sequence` (sequence operators are _not_ inline).

I'll try it as soon as I get back to the 'puter. :)