Question

How to check if a word is all uppercase or lowercase or capitalized in Scala

Answer 1

object CasingVerifier {

  def verifyAllUpperOrAllLowerOrIsCapitalized(word: String): Boolean = {
    val (upper, lower) = word.foldLeft((0, 0)) {
      case ((u, l), ch) if ch.isLower => (u, l + 1)
      case ((u, l), ch) if ch.isUpper => (u + 1, l)
      case (acc, _) => acc
    }

    // Case 1: all lowercase
    if (upper == 0) true
    // Case 2: all uppercase
    else if (lower == 0) true
    // Case 3: capitalized (only first letter uppercase)
    else if (upper == 1 && word.headOption.exists(_.isUpper)) true
    // Otherwise, mixed casing
    else false
  }

  def runTest(word: String): Unit = {
    println(s"""Testing word: "$word"""")
    if (verifyAllUpperOrAllLowerOrIsCapitalized(word)) {
      println("OK\n")
    } else {
      println("Error\n")
    }
  }

  def main(args: Array[String]): Unit = {
    runTest("PROGRAMMING")   
    runTest("programming")   
    runTest("Programming")  
    runTest("ProGramMing")   
  }
}



/*
run:

Testing word: "PROGRAMMING"
OK

Testing word: "programming"
OK

Testing word: "Programming"
OK

Testing word: "ProGramMing"
Error

*/

 

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