Collection operations / published by https://github.com/dacr/code-examples-manager #3783b8e4-99a6-44b4-b106-d06cd5646a96/bc65c08d46a0e90b2e74fc4eb6a5e91faeaf5c6f

collection-operations.sc

// summary : Collection operations
// keywords : scala, scalatest, collection, cheatsheet, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 3783b8e4-99a6-44b4-b106-d06cd5646a96
// created-on : 2021-03-04T20:00:03Z
// 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 java.text.spi.DecimalFormatSymbolsProvider
import java.text.{DecimalFormat, DecimalFormatSymbols, NumberFormat}

import org.scalatest._
import flatspec._
import matchers._

class CollectionOperations extends AnyFlatSpec with should.Matchers {
  override def suiteName="CollectionOperations"
  // ---------------------------------------------------------------------------------------------
  "A collection" should "support safe get by index with lift" in {
    Array(42).lift(0) shouldBe Some(42)
    Array(42).lift(42) shouldBe None
    Array(42).lift(-42) shouldBe None
    List("a","b","c").lift(2) shouldBe Some("c")
    List("a","b","c").lift(42) shouldBe None
    List("a","b","c").lift(-42) shouldBe None
  }
  // ---------------------------------------------------------------------------------------------
  it should "replace any kind of loop without any constraint" in {
    info("iterator .iterate advantageously .from method as it fully generic")
    LazyList
      .iterate(10L)(_ + 1)
      .zip(Iterator.iterate(0L)(_ + 1))
      .takeWhile{ case(value, index) => index < 5}
      .map{ case (value, index)=>value}
      .sum shouldBe 10+11+12+13+14
  }
  // ---------------------------------------------------------------------------------------------
}

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