How to suppress “match is not exhaustive!” warning in Scala

Question

How can I suppress the \"match is not exhaustive!\" warning in the following Scala code?

val l = \"1\" :: \"2\" :: Nil
l.sliding(2).foreach{case List(a,b) =&         


        

Answer 1

Here are several options:

1. You can match against Seq instead of List, since Seq doesn't have the exhaustiveness checking (this will fail, like your original, on one element lists):

   l.sliding(2).foreach{case Seq(a, b) => ... }
   

2. You can use a for comprehension, which will silently discard anything that doesn't match (so it will do nothing on one element lists):

   for (List(a, b) <- l.sliding(2)) { ... }
   

3. You can use collect, which will also silently discard anything that doesn't match (and where you'll get an iterator back, which you'll have to iterate through if you need to):

   l.sliding(2).collect{case List(a,b) => }.toList