Advanced operations on strings / published by https://github.com/dacr/code-examples-manager #61e8e69d-edf9-421b-b56c-8a2da754a8d3/6cc5d08eb816b4aa1c584ff9a0ce9d83d350d597

string-operations.sc

// summary : Advanced operations on strings
// keywords : scala, scalatest, strings, cheatsheet, @testable
// publish : gist
// authors : David Crosson
// license : Apache License Version 2.0 (https://www.apache.org/licenses/LICENSE-2.0.txt)
// id : 61e8e69d-edf9-421b-b56c-8a2da754a8d3
// created-on : 2020-05-31T21:54:52+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "3.4.2"
//> using dep "org.scalatest::scalatest:3.2.16"
//> using objectWrapper
// ---------------------

import org.scalatest._
import flatspec._
import matchers._
import OptionValues._
import java.util.Locale
import java.text.{DecimalFormat, NumberFormat}

class AdvancedStringOperations extends AnyFlatSpec with should.Matchers {
  override def suiteName="AdvancedStringOperations"

  // ---------------------------------------------------------------------------------------------
  "interpolators" should "allow advanced string formatting" in {
    Locale.setDefault(Locale.US) // TODO - find better alternative
    val m="machin"
    val x=42
    val bx=42042
    val f=42.42d
    val bf=2442.42d
    val d=0.42d
    s"truc-$m" shouldBe "truc-machin"
    raw"truc-$x\nsameline" shouldBe """truc-42\nsameline"""
    raw"truc-$x\nsameline" shouldBe "truc-42\\nsameline"
    // ---- strings
    f"truc-$m%10s-bidule" shouldBe "truc-    machin-bidule"
    f"truc-$m%-10s-bidule" shouldBe "truc-machin    -bidule"
    // ---- int, long
    f"truc-$x%d-bidule" shouldBe "truc-42-bidule"
    f"truc-$x%05d-bidule" shouldBe "truc-00042-bidule"
    f"truc-$bx%,d-bidule" shouldBe "truc-42,042-bidule" // or space instead of comma in french locale
    f"truc-$d%.1f-bidule" shouldBe "truc-0.4-bidule"
    // ---- double,float
    f"truc-$f%6.1f-bidule" shouldBe "truc-  42.4-bidule"
    f"truc-$f%06.1f-bidule" shouldBe "truc-0042.4-bidule"
    f"truc-$f%-6.1f-bidule" shouldBe "truc-42.4  -bidule"
    f"truc-$bf%#,8.1f-bidule" shouldBe "truc- 2,442.4-bidule"
  }

  // ---------------------------------------------------------------------------------------------
  "pattern matching with string interpolators" should "be possible since scala 2.13" in {
    val name = "hello dave !" match { // of course to be "safe" add a case capture for all other cases
      case s"hello $name !" => name
    }
    name shouldBe "dave"
  }

  it should "also be possible with this alternative syntax" in {
    val s"hello $name !" = "hello dave !"  // of course it is not "safe"
    name shouldBe "dave"
  }

  "numbers" should "be extracted from strings with Locale taken into account" in {
    val nf = NumberFormat.getInstance(Locale.FRENCH)
    nf.parse("123,42").doubleValue() shouldBe 123.42
    nf.parse("32123,42").doubleValue() shouldBe 32123.42
  }

  it should "be possible to take into account custom thousands separator (US)" in {
    val nf = NumberFormat.getInstance(Locale.US).asInstanceOf[DecimalFormat]
    val symbols = nf.getDecimalFormatSymbols
    symbols.setGroupingSeparator(' ')
    nf.setDecimalFormatSymbols(symbols)
    nf.setGroupingUsed(true)
    nf.parse("-32 123.42").doubleValue() shouldBe -32123.42
  }

  it should "be possible to take into account custom thousands separator (FR)" in {
    val nf = NumberFormat.getInstance(Locale.FRENCH).asInstanceOf[DecimalFormat]
    val symbols = nf.getDecimalFormatSymbols
    symbols.setGroupingSeparator(' ')
    nf.setDecimalFormatSymbols(symbols)
    nf.setGroupingUsed(true)
    nf.parse("-32 123,42").doubleValue() shouldBe -32123.42
  }

}

org.scalatest.tools.Runner.main(Array("-oDF", "-s", classOf[AdvancedStringOperations].getName))