CODEWITHSUNDEEP
scalapattern-matching
ffff
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Reputation: 3070

Scala pattern matching variable binding with auto type conversion

In scala we can pattern match on types. So is it possible to bind a variable to the matched pattern with the type. Right now the bounded variable has type Any

val a: Any = "hello"
a match {
     case v @ String {
          v.length() // not working
     }
}

Upvotes: 0

Views: 349

Answers (2)

echo
echo

Reputation: 1291

To pattern match on a type follow the syntax exposed in @chengpohi .

The bind operator @ is used to refer to a (sub)structure of the data extracted in pattern matching. For example in

("hello",123) match {
  case t @ (fst: String, snd: Int) => println(s"got tuple $t")
  case _                           =>
}

label t refers to the entire tuple, not having to denote fst and snd.

Upvotes: 0

chengpohi
chengpohi

Reputation: 14227

Your syntax is not correct!!!, it should be like:

val a: Any = "hello"
a match {
     case v: String => v.length()
}

use : to match type, and => with the next block

Upvotes: 4

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