ScalaのObject内で良くセットで定義されるメソッド、 apply (注入、injection)、unapply(抽出、extraction)。 細かい事はコップ本26章やその他の有用な記事を見るとして... unapplyメソッドを持つオブジェクトは抽出子(extractorObject)と呼ばれる。 例1 object extractorObject { // 抽出子オブジェクト object Sample { def apply(str: String): String = { // 文字列を作った str + " (applyが呼ばれた)" } // ここでの引数strはapplyが作り出した文字列 def unapply(str: String): Option[String] = { if (str.nonEmpty) Some(str + (" (unapplyも呼ばれ
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