2016 Update

Task/Remove-duplicate-elements/Groovy/remove-duplicate-elements.groovy

@@ -1,21 +1,22 @@
 def list = [1, 2, 3, 'a', 'b', 'c', 2, 3, 4, 'b', 'c', 'd']
 assert list.size() == 12
-println "   Original List: ${list}"
+println "             Original List: ${list}"
 
-// Filtering the List
+// Filtering the List (non-mutating)
+def list2 = list.unique(false)
+assert list2.size() == 8
+assert list.size() == 12
+println "             Filtered List: ${list2}"
+
+// Filtering the List (in place)
 list.unique()
 assert list.size() == 8
-println "   Filtered List: ${list}"
+println "   Original List, filtered: ${list}"
 
-list = [1, 2, 3, 'a', 'b', 'c', 2, 3, 4, 'b', 'c', 'd']
-assert list.size() == 12
+def list3 = [1, 2, 3, 'a', 'b', 'c', 2, 3, 4, 'b', 'c', 'd']
+assert list3.size() == 12
 
 // Converting to Set
-def set = new HashSet(list)
+def set = list as Set
 assert set.size() == 8
-println "             Set: ${set}"
-
-// Converting to Order-preserving Set
-set = new LinkedHashSet(list)
-assert set.size() == 8
-println "List-ordered Set: ${set}"
+println "                       Set: ${set}"