Just another update

Task/Collections/Scala/collections-2.scala

@@ -0,0 +1,30 @@
+    import collection.concurrent.TrieMap
+
+    // super concurrent mutable hashmap
+    val map = TrieMap("Amsterdam" -> "Netherlands",
+      "New York" -> "USA",
+      "Heemstede" -> "Netherlands")
+
+    map("Laussanne") = "Switzerland" // 2 Ways of updating
+    map += ("Tokio" -> "Japan")
+
+    assert(map("New York") == "USA")
+    assert(!map.isDefinedAt("Gent")) // isDefinedAt is false
+    assert(map.isDefinedAt("Laussanne")) // true
+
+    val hash = new TrieMap[Int, Int]
+    hash(1) = 2
+    hash += (1 -> 2) // same as hash(1) = 2
+    hash += (3 -> 4, 5 -> 6, 44 -> 99)
+    hash(44) // 99
+    hash.contains(33) // false
+    hash.isDefinedAt(33) // same as contains
+    hash.contains(44) // true
+    // iterate over key/value
+    //    hash.foreach { case (key, val) => println(  "key " + e._1 + " value " + e._2) } // e is a 2 element Tuple
+    // same with for syntax
+    for ((k, v) <- hash) println("key " + k + " value " + v)
+    //    // items in map where the key is greater than 3
+        map.filter { k => k._1 > 3 } //  Map(5 -> 6, 44 -> 99)
+    //    // same with for syntax
+        for ((k, v) <- map; if k > 3) yield (k, v)