Help/Collections/Set.html

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  37 <p class="p1"><span class="s1"><b>Set<span class="Apple-tab-span">      </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span></b></span><b>a set according to equality</b></p>
  38 <p class="p2"><br></p>
  39 <p class="p1"><b>Inherits from: </b><a href="../Core/Object.html"><span class="s2"><b>Object</b></span></a><b> : </b><a href="Collection.html"><span class="s2"><b>Collection</b></span></a><span class="s2"><b><span class="Apple-converted-space"> </span></b></span></p>
  40 <p class="p2"><br></p>
  41 <p class="p1">A Set is s collection of objects, no two of which are equal.</p>
  42 <p class="p1">Most of its methods are inherited from Collection.</p>
  43 <p class="p1">The contents of a Set are unordered. You must not depend on the order of items in a set.</p>
  44 <p class="p1">For an ordered set, see <a href="OrderedIdentitySet.html"><span class="s3">OrderedIdentitySet</span></a>.</p>
  45 <p class="p2"><br></p>
  46 <p class="p3"><span class="s4">See also: <a href="IdentitySet.html"><span class="s5">IdentitySet</span></a>, <a href="List.html"><span class="s5">List</span></a>, <a href="Dictionary.html"><span class="s5">Dictionary</span></a></span></p>
  47 <p class="p2"><br></p>
  48 <p class="p4"><b></b><br></p>
  49 <p class="p5"><b>Adding and Removing:</b></p>
  50 <p class="p2"><br></p>
  51 <p class="p1"><b>add(anObject)</b></p>
  52 <p class="p2"><br></p>
  53 <p class="p1">Add anObject to the Set. An object which is equal to an object already in the Set will not be added.</p>
  54 <p class="p6"><br></p>
  55 <p class="p7"><span class="s2">Set</span>[1, 2, 3].add(4).postln;</p>
  56 <p class="p8"><br></p>
  57 <p class="p7"><span class="s2">Set</span>[1, 2, 3].add(3).postln;</p>
  58 <p class="p8"><br></p>
  59 <p class="p7"><span class="s2">Set</span>[<span class="s6">"abc"</span>, <span class="s6">"def"</span>, <span class="s6">"ghi"</span>].add(<span class="s6">"jkl"</span>).postln;</p>
  60 <p class="p8"><br></p>
  61 <p class="p9"><span class="s2">Set</span><span class="s4">[</span>"abc"<span class="s4">, </span>"def"<span class="s4">, </span>"ghi"<span class="s4">].add(</span>"def"<span class="s4">).postln;</span></p>
  62 <p class="p2"><br></p>
  63 <p class="p1"><b>remove(anObject)</b></p>
  64 <p class="p2"><br></p>
  65 <p class="p1">Remove anObject from the Set.</p>
  66 <p class="p2"><br></p>
  67 <p class="p7"><span class="s2">Set</span>[1, 2, 3].remove(3).postln;</p>
  68 <p class="p6"><br></p>
  69 <p class="p10"><br></p>
  70 <p class="p5"><b>Iteration:</b></p>
  71 <p class="p2"><br></p>
  72 <p class="p1"><b>do(function)</b></p>
  73 <p class="p2"><br></p>
  74 <p class="p1">Evaluates function for each item in the Set.</p>
  75 <p class="p1">The function is passed two arguments, the item and an integer index.</p>
  76 <p class="p2"><br></p>
  77 <p class="p7"><span class="s2">Set</span>[1, 2, 3, 300].do({ <span class="s2">arg</span> item, i; item.postln });</p>
  78 <p class="p8"><br></p>
  79 <p class="p1"><b>keyAt(index)</b></p>
  80 <p class="p2"><br></p>
  81 <p class="p1">returns the object at the internal <b>index</b>. This index is not deterministic.</p>
  82 <p class="p2"><br></p>
  83 <p class="p2"><br></p>
  84 <p class="p2"><br></p>
  85 <p class="p5"><b>Set specific operations:</b></p>
  86 <p class="p4"><b></b><br></p>
  87 <p class="p2"><br></p>
  88 <p class="p1"><b>sect(that)</b><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>return the set theoretical intersection of <b>this</b> and <b>that</b></p>
  89 <p class="p1"><b>this &amp; that</b></p>
  90 <p class="p8"><br></p>
  91 <p class="p7">a = <span class="s7">Set</span>[1, 2, 3]; b = <span class="s7">Set</span>[2, 3, 4, 5];</p>
  92 <p class="p7">sect(a, b);</p>
  93 <p class="p11"><span class="s4">a &amp; b </span>// shorter syntax</p>
  94 <p class="p2"><br></p>
  95 <p class="p1"><b>union(that)</b><span class="Apple-tab-span">   </span><span class="Apple-tab-span">    </span>return the set theoretical union of <b>this</b> and <b>that</b></p>
  96 <p class="p1"><b>this | that</b></p>
  97 <p class="p12"><br></p>
  98 <p class="p13">a = <span class="s7">Set</span>[1, 2, 3]; b = <span class="s7">Set</span>[2, 3, 4, 5];</p>
  99 <p class="p13">union(a, b);</p>
 100 <p class="p11"><span class="s4">a | b </span>// shorter syntax</p>
 101 <p class="p2"><br></p>
 102 <p class="p1"><b>difference(that)<span class="Apple-tab-span">  </span></b><span class="Apple-tab-span">        </span>return the set of all items which are elements of <b>this</b>, but not of <b>that</b></p>
 103 <p class="p1"><b>this - that</b></p>
 104 <p class="p8"><br></p>
 105 <p class="p7">a = <span class="s7">Set</span>[1, 2, 3]; b = <span class="s7">Set</span>[2, 3, 4, 5];</p>
 106 <p class="p7">difference(a, b);</p>
 107 <p class="p11"><span class="s4">a - b </span>// shorter syntax</p>
 108 <p class="p2"><br></p>
 109 <p class="p1"><b>symmetricDifference(that)</b><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>return the set of all items which are not elements of both<span class="Apple-converted-space">  </span><b>this</b> and <b>that</b></p>
 110 <p class="p1"><b>this -- that</b></p>
 111 <p class="p8"><br></p>
 112 <p class="p7">a = <span class="s7">Set</span>[1, 2, 3]; b = <span class="s7">Set</span>[2, 3, 4, 5];</p>
 113 <p class="p7">symmetricDifference(a, b);</p>
 114 <p class="p11"><span class="s4">a -- b </span>// shorter syntax</p>
 115 <p class="p2"><br></p>
 116 <p class="p1"><b>isSubsetOf(that)</b><span class="Apple-tab-span">      </span>returns true if all elements of <b>this</b> are also elements of <b>that</b><span class="Apple-converted-space"> </span></p>
 117 <p class="p2"><br></p>
 118 <p class="p13">a = <span class="s7">Set</span>[1, 2, 3, 4];</p>
 119 <p class="p13"><span class="s7">Set</span>[1, 2].isSubsetOf(a); <span class="s8">// true</span></p>
 120 <p class="p13"><span class="s7">Set</span>[1, 5].isSubsetOf(a); <span class="s8">// false</span></p>
 121 <p class="p2"><br></p>
 122 <p class="p2"><br></p>
 123 <p class="p14"><br></p>
 124 <p class="p11">// example:</p>
 125 <p class="p12"><br></p>
 126 <p class="p13">a = <span class="s7">Set</span>[1, 2, 3, 4];</p>
 127 <p class="p11"><span class="s4">b = a.powerset; </span>// set of all parts</p>
 128 <p class="p11"><span class="s4">a.isSubsetOf(b); </span>// false: no set is ever part of itself.</p>
 129 <p class="p11"><span class="s4">b.asArray.reduce(</span><span class="s9">\union</span><span class="s4">) == a; </span>// true parts may not contain other elements that original</p>
 130 <p class="p13">b.asArray.reduce(<span class="s9">\difference</span>).isEmpty; <span class="s8">// true.</span></p>
 131 <p class="p12"><br></p>
 132 <p class="p11">// you can use Set to efficiently remove duplicates from an array:</p>
 133 <p class="p12"><br></p>
 134 <p class="p13">a = [1, 2, 3, 4, 3, 5, 5, 2, 2, 1];</p>
 135 <p class="p11"><span class="s4">a.as(</span><span class="s7">Set</span><span class="s4">);<span class="Apple-tab-span"> </span></span>// convert to set</p>
 136 <p class="p11"><span class="s4">a.as(</span><span class="s7">Set</span><span class="s4">).as(</span><span class="s7">Array</span><span class="s4">); </span>// and convert back</p>
 137 <p class="p14"><br></p>
 138 <p class="p14"><br></p>
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