Just another update

Task/Collections/00DESCRIPTION

@@ -1,4 +1,6 @@
-{{clarified-review}}Collections are abstractions to represent sets of values.  In statically-typed languages, the values are typically of a common data type.
+{{clarified-review}}
+Collections are abstractions to represent sets of values.
+In statically-typed languages, the values are typically of a common data type.
 
 Create a collection, and add a few values to it.
 

Task/Collections/00META.yaml

@@ -1,2 +1,4 @@
 ---
+category:
+- Data Structures
 note: Basic language learning

Task/Collections/Java/collections-5.java

@@ -4,7 +4,7 @@ import scala.collection.immutable.HashSet;
 import scala.collection.mutable.ArrayBuffer;
 
 public class Collections {
-	
+
 	public static void main(String[] args) {
 		ArrayBuffer<Integer> myarrlist = new ArrayBuffer<Integer>();
 		ArrayBuffer<Integer> myarrlist2 = new ArrayBuffer<Integer>(20);
@@ -13,9 +13,6 @@ public class Collections {
 		myarrlist.$plus$eq(13); // to add an element.
 		myarrlist.$plus$eq(-1);
 
-		myarrlist2.$plus$plus$eq(myarrlist);// //$plus$plus$eq is Scala ++= operator
-		myarrlist2.$plus$plus$eq(myarrlist);
-
 		myarrlist2 = (ArrayBuffer<Integer>) myarrlist2.$minus(-1);
 
 		for (int i = 0; i < 10; i++)

Task/Collections/Maple/collections-1.maple

@@ -0,0 +1,5 @@
+L1 := [3, 4, 5, 6];
+                     L1 := [3, 4, 5, 6]
+
+L2 := [7, 8, 9];
+                       L2 := [7, 8, 9]

Task/Collections/Maple/collections-2.maple

@@ -0,0 +1,2 @@
+[op(L1), op(L2)]
+                    [3, 4, 5, 6, 7, 8, 9]

Task/Collections/Maple/collections-3.maple

@@ -0,0 +1,2 @@
+A1 := Array([3, 4, 5, 6]);
+                     A1 := [3, 4, 5, 6]

Task/Collections/Maple/collections-4.maple

@@ -0,0 +1,2 @@
+ArrayTools:-Append(A1, 7);
+              A1 := [3, 4, 5, 6, 7]

Task/Collections/Ruby/collections-1.rb

@@ -1,5 +1,4 @@
 # creating an empty array and adding values
-
 a = []              #=> []
 a[0] = 1            #=> [1]
 a[3] = "abc"        #=> [1, nil, nil, "abc"]

Task/Collections/Ruby/collections-2.rb

@@ -1,5 +1,4 @@
 # creating an empty hash
-
 h = {}              #=> {}
 h["a"] = 1          #=> {"a"=>1}
 h["test"] = 2.4     #=> {"a"=>1, "test"=>2.4}

Task/Collections/Ruby/collections-4.rb

@@ -0,0 +1,21 @@
+require 'set'
+
+# different ways of creating a set
+p s1 = Set[1, 2, 3, 4]          #=> #<Set: {1, 2, 3, 4}>
+p s2 = [8, 6, 4, 2].to_set      #=> #<Set: {8, 6, 4, 2}>
+p s3 = Set.new(1..4) {|x| x*2}  #=> #<Set: {2, 4, 6, 8}>
+
+# Union
+p s1 | s2                       #=> #<Set: {1, 2, 3, 4, 8, 6}>
+# Intersection
+p s1 & s2                       #=> #<Set: {4, 2}>
+# Difference
+p s1 - s2                       #=> #<Set: {1, 3}>
+
+p s1 ^ s2                       #=> #<Set: {8, 6, 1, 3}>
+
+p s2 == s3                      #=> true
+
+p s1.add(5)                     #=> #<Set: {1, 2, 3, 4, 5}>
+p s1 << 0                       #=> #<Set: {1, 2, 3, 4, 5, 0}>
+p s1.delete(3)                  #=> #<Set: {1, 2, 4, 5, 0}>

Task/Collections/Ruby/collections-5.rb

@@ -0,0 +1,24 @@
+require 'matrix'
+
+# creating a matrix
+p m0 = Matrix.zero(3)       #=> Matrix[[0, 0, 0], [0, 0, 0], [0, 0, 0]]
+p m1 = Matrix.identity(3)   #=> Matrix[[1, 0, 0], [0, 1, 0], [0, 0, 1]]
+p m2 = Matrix[[11, 12], [21, 22]]
+                            #=> Matrix[[11, 12], [21, 22]]
+p m3 = Matrix.build(3) {|row, col| row - col}
+                            #=> Matrix[[0, -1, -2], [1, 0, -1], [2, 1, 0]]
+
+p m2[0,0]               #=> 11
+p m1 * 5                #=> Matrix[[5, 0, 0], [0, 5, 0], [0, 0, 5]]
+p m1 + m3               #=> Matrix[[1, -1, -2], [1, 1, -1], [2, 1, 1]]
+p m1 * m3               #=> Matrix[[0, -1, -2], [1, 0, -1], [2, 1, 0]]
+
+# creating a Vector
+p v1 = Vector[1,3,5]    #=> Vector[1, 3, 5]
+p v2 = Vector[0,1,2]    #=> Vector[0, 1, 2]
+p v1[1]                 #=> 3
+p v1 * 2                #=> Vector[2, 6, 10]
+p v1 + v2               #=> Vector[1, 4, 7]
+
+p m1 * v1               #=> Vector[1, 3, 5]
+p m3 * v1               #=> Vector[-13, -4, 5]

Task/Collections/Ruby/collections-6.rb

@@ -0,0 +1,23 @@
+require 'ostruct'
+
+# creating a OpenStruct
+ab = OpenStruct.new
+p ab                #=> #<OpenStruct>
+ab.foo = 25
+p ab.foo            #=> 25
+ab[:bar] = 2
+p ab["bar"]         #=> 2
+p ab                #=> #<OpenStruct foo=25, bar=2>
+ab.delete_field("foo")
+p ab.foo            #=> nil
+p ab                #=> #<OpenStruct bar=2>
+
+p son = OpenStruct.new({ :name => "Thomas", :age => 3 })
+                    #=> #<OpenStruct name="Thomas", age=3>
+p son.name          #=> "Thomas"
+p son[:age]         #=> 3
+son.age += 1
+p son.age           #=> 4
+son.items = ["candy","toy"]
+p son.items         #=> ["candy","toy"]
+p son               #=> #<OpenStruct name="Thomas", age=4, items=["candy", "toy"]

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)

Task/Collections/Scheme/collections-3.ss

@@ -1,2 +1 @@
-(1 2 3)
-()
+(cons obj lst)

Task/Collections/Scheme/collections-4.ss

@@ -1 +1,2 @@
-(cons obj lst)
+(display (cons 0 (list 1 2 3)))
+(newline)

Task/Collections/Scheme/collections-5.ss

@@ -1,2 +1 @@
-(display (cons 0 (list 1 2 3)))
-(newline)
+(append lst ...)

Task/Collections/Scheme/collections-6.ss

@@ -1 +1,2 @@
-(0 1 2 3)
+(display (append (list 1 2 3) (list 4 5 6)))
+(newline)

Task/Collections/UNIX-Shell/collections-1.sh

@@ -0,0 +1,9 @@
+a_index=(one two three)           # create an array with a few elements
+a_index+=(four five)              # append some elements
+a_index[9]=ten                   # add a specific index
+for elem in "${a_index[@]}"; do   # interate over the elements
+    echo "$elem"
+done
+for idx in "${!a_index[@]}"; do   # interate over the array indices
+    printf "%d\t%s\n" $idx "${a_index[idx]}"
+done

Task/Collections/UNIX-Shell/collections-2.sh

@@ -0,0 +1,9 @@
+declare -A a_assoc=([one]=1 [two]=2 [three]=3)    # create an array with a few elements
+a_assoc+=([four]=4 [five]=5)                      # add some elements
+a_assoc[ten]=10
+for value in "${a_assoc[@]}"; do                  # interate over the values
+    echo "$value"
+done
+for key in "${!a_assoc[@]}"; do                   # interate over the array indices
+    printf "%s\t%s\n" "$key" "${a_assoc[$key]}"
+done

Task/Collections/UNIX-Shell/collections-3.sh

@@ -0,0 +1 @@
+declare -A

Task/Collections/UNIX-Shell/collections-4.sh

@@ -0,0 +1 @@
+typeset -A