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POHow to access and update a value in a mutable map of map of maps
 

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  1. POHow to access and update a value in a mutable map of map of maps
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    <p>I've a three-level data structure (indentation and line breaks for readability):</p> <pre><code>scala&gt; import scala.collection.mutable.Map import scala.collection.mutable.Map scala&gt; val m = Map("normal" -&gt; Map("home" -&gt; Map("wins" -&gt; 0, "scores" -&gt; 0), "away" -&gt; Map("wins" -&gt; 0, "scores" -&gt; 0))) m: scala.collection.mutable.Map[java.lang.String, scala.collection.mutable.Map[java.lang.String, scala.collection.mutable.Map[java.lang.String,Int]]] = Map((normal,Map(away -&gt; Map(wins -&gt; 0, scores -&gt; 0), home -&gt; Map(wins -&gt; 0, scores -&gt; 0)))) </code></pre> <p>Accessing the innermost data (scores) requires a lot of typing:</p> <pre><code>import org.scalatest.{Assertions, FunSuite} class MapExamplesSO extends FunSuite with Assertions { test("Update values in a mutable map of map of maps") { import scala.collection.mutable.Map // The m map is essentially an accumulator val m = Map("normal" -&gt; Map("home" -&gt; Map("wins" -&gt; 0, "scores" -&gt; 0), "away" -&gt; Map("wins" -&gt; 0, "scores" -&gt; 0) ) ) // // Is there a less verbose way to increment the scores ? // assert(m("normal").apply("home").apply("scores") === 0) val s1 = m("normal").apply("home").apply("scores") + 1 m("normal").apply("home").update("scores", s1) assert(m("normal").apply("home").apply("scores") === 1) val s2 = m("normal").apply("home").apply("scores") + 2 m("normal").apply("home").update("scores", s2) assert(m("normal").apply("home").apply("scores") === 3) } } </code></pre> <p>Is there a less verbose way to modify the value of scores ?</p> <p>I'm a Scala newbie, so all other observations of the code above are also welcome.</p>
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