Scala polymorphic function for filtering an input List of Either

Question

Seeking a more elegant solution I have this piece of code, I just use it in test cases where it isn't necessary to do any error handling. What it does is: - take an input list of strings - parse them using the DSJSonmapper.parseDSResult method - filters them and extracts the Right value from each Either (Left is an Exception) The code is as follows: ``` def parseDs(ins: List[String]) = { def filterResults[U, T](in: List[Either[U, T]]): List[T] = { in.filter(y => y.isRight).map(z => z.right.get) } filterResults(ins.map(x => DSJsonMapper.parseDSResult(x))) } ``` Now, I haven't done an awful lot of polymorphic functions, but this works. However I feel like it's a bit ugly. Has anyone got a better suggestion, how to accomplish the same thing. I'm aware this is going to come down to a case of personal preference. But suggestions are welcome.

Accepted Answer

`collect` is made for exactly this kind of situation:

```
def filterMe[U,T](in: List[Either[U,T]]): List[T] = in.collect{
  case Right(r) => r
}
```

In fact, it's so good at this you may want to skip the `def` and just

```
ins.map(DSJsonMapper.parseDsResult).collect{ case Right(r) => r }
```

Scala polymorphic function for filtering an input List of Either

Solution

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