sample code for remove digits tutorial

Author: pedrorijo91

scala-core-modules/scala-core-numbers/src/main/scala/com/baeldung/scala/digits/RemoveDigits.scala

@@ -0,0 +1,45 @@
+package com.baeldung.scala.digits
+
+object RemoveDigits {
+
+  def removeFirstNDigits(num: Int, n: Int): Int = {
+    num.toString.drop(n).toInt
+  }
+
+  def removeFirstNDigitsLimit(num: Int, n: Int): Int = {
+    val numString = num.toString
+    if (n >= numString.length)
+      0
+    else
+      numString.drop(n).toInt
+  }
+
+  def removeFirstNDigitsPatternMatching(num: Int, n: Int): Int = {
+    val numString = num.toString
+    numString match {
+      case str if n >= str.length =>
+        0
+      case str =>
+        str.drop(n).toInt
+    }
+  }
+
+  def removeFirstNDigitsNegative(num: Int, n: Int): Int = {
+    val numString = num.toString
+    if (num < 0) {
+      // For negative numbers, remove the first n digits but keep the negative sign
+      val absNumString = numString.drop(1) // Drop the negative sign
+      if (n >= absNumString.length)
+        0
+      else
+        ("-" + absNumString.drop(n)).toInt
+    } else {
+      // For positive numbers, apply the same logic as before
+      if (n >= numString.length)
+        0
+      else
+        numString.drop(n).toInt
+    }
+  }
+
+}

scala-core-modules/scala-core-numbers/src/test/scala/com/baeldung/scala/digits/RemoveDigitsUnitTest.scala

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+package com.baeldung.scala.digits
+
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+class RemoveDigitsUnitTest extends AnyFlatSpec with Matchers {
+
+  val number = 123456
+  val negativeNumber = -number
+
+  "naive" should "return remove first N digits" in {
+    RemoveDigits.removeFirstNDigits(number, 2) shouldBe 3456
+    RemoveDigits.removeFirstNDigits(number, 5) shouldBe 6
+  }
+
+  "limit" should "return remove first N digits" in {
+    RemoveDigits.removeFirstNDigitsLimit(number, 2) shouldBe 3456
+    RemoveDigits.removeFirstNDigitsLimit(number, 5) shouldBe 6
+    RemoveDigits.removeFirstNDigitsLimit(number, 6) shouldBe 0
+  }
+
+  "patternMatching" should "return remove first N digits" in {
+    RemoveDigits.removeFirstNDigitsPatternMatching(number, 2) shouldBe 3456
+    RemoveDigits.removeFirstNDigitsPatternMatching(number, 5) shouldBe 6
+    RemoveDigits.removeFirstNDigitsPatternMatching(number, 6) shouldBe 0
+  }
+
+  "negative" should "return remove first N digits" in {
+    RemoveDigits.removeFirstNDigitsNegative(number, 2) shouldBe 3456
+    RemoveDigits.removeFirstNDigitsNegative(number, 5) shouldBe 6
+    RemoveDigits.removeFirstNDigitsNegative(number, 6) shouldBe 0
+    RemoveDigits.removeFirstNDigitsNegative(negativeNumber, 2) shouldBe -3456
+  }
+
+}