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Hoppinglife (talk | contribs) Created page with "== Pattern Matching on Seq == <pre class="hljs"> def f(ints: Seq[Int]): String = ints match { case Seq() => "The Seq is empty !" case Seq(first) => s"The seq..." |
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== Pattern Matching on Seq == | == Pattern Matching on Seq == | ||
< | <syntaxhighlight lang="scala"> | ||
def f(ints: Seq[Int]): String = ints match { | def f(ints: Seq[Int]): String = ints match { | ||
case Seq() => | case Seq() => | ||
| Line 30: | Line 31: | ||
"The seq didn't match any of the above, so it must be empty" | "The seq didn't match any of the above, so it must be empty" | ||
} | } | ||
</ | |||
</syntaxhighlight> | |||
See [https://riptutorial.com/scala/example/3056/pattern-matching-on-a-seq#:~:text=In%20general%2C%20any%20form%20that,and%20can%20have%20unexpected%20results. here] | |||
Latest revision as of 22:16, 7 June 2020
Pattern Matching on Seq
def f(ints: Seq[Int]): String = ints match {
case Seq() =>
"The Seq is empty !"
case Seq(first) =>
s"The seq has exactly one element : $first"
case Seq(first, second) =>
s"The seq has exactly two elements : $first, $second"
case s @ Seq(_, _, _) =>
s"s is a Seq of length three and looks like ${s}" // Note individual elements are not bound to their own names.
case s: Seq[Int] if s.length == 4 =>
s"s is a Seq of Ints of exactly length 4" // Again, individual elements are not bound to their own names.
case _ =>
"No match was found!"
}
def f(ints: Seq[Int]): String = ints match {
case Seq(first, second, tail @ _*) =>
s"The seq has at least two elements : $first, $second. The rest of the Seq is $tail"
case Seq(first, tail @ _*) =>
s"The seq has at least one element : $first. The rest of the Seq is $tail"
// alternative syntax
// here of course this one will never match since it checks
// for the same thing as the one above
case first +: tail =>
s"The seq has at least one element : $first. The rest of the Seq is $tail"
case _ =>
"The seq didn't match any of the above, so it must be empty"
}
See here