141 lines
2.9 KiB
Racket
141 lines
2.9 KiB
Racket
#lang scribble/manual
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@(require (for-label racket))
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@title{Set}
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a set according to equality@section{related}
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Classes/IdentitySet, Classes/List, Classes/Dictionary
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@section{categories}
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Collections>Unordered
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@section{description}
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A Set is s collection of objects, no two of which are equal. Most of its methods are inherited from Collection. The contents of a Set are unordered. You must not depend on the order of items in a set. For an ordered set, see link::Classes/OrderedIdentitySet::.
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@section{INSTANCEMETHODS}
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@section{private}
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initSet, putCheck, fullCheck, grow, noCheckAdd
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@section{subsection}
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Adding and Removing
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@section{method}
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add
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Add anObject to the Set. An object which is equal to an object already in the Set will not be added.
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@racketblock[
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Set[1, 2, 3].add(4).postln;
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Set[1, 2, 3].add(3).postln;
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Set["abc", "def", "ghi"].add("jkl").postln;
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Set["abc", "def", "ghi"].add("def").postln;
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::
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]
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@section{method}
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remove
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Remove anObject from the Set.
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@racketblock[
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Set[1, 2, 3].remove(3).postln;
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::
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]
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@section{subsection}
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Iteration
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@section{method}
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do
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Evaluates function for each item in the Set. The function is passed two arguments, the item and an integer index.
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@racketblock[
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Set[1, 2, 3, 300].do({ arg item, i; item.postln });
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::
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]
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@section{method}
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keyAt
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Returns the object at the internal strong::index::. This index is not deterministic.
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@section{subsection}
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Set specific operations
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@section{method}
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sect, &
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Return the set theoretical intersection of this and strong::that::.
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@racketblock[
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a = Set[1, 2, 3]; b = Set[2, 3, 4, 5];
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sect(a, b);
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a & b // shorter syntax
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::
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]
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@section{method}
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union, |
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Return the set theoretical union of this and strong::that::.
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@racketblock[
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a = Set[1, 2, 3]; b = Set[2, 3, 4, 5];
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union(a, b);
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a | b // shorter syntax
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::
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]
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@section{method}
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difference, -
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Return the set of all items which are elements of this, but not of strong::that::.
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@racketblock[
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a = Set[1, 2, 3]; b = Set[2, 3, 4, 5];
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difference(a, b);
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a - b // shorter syntax
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::
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]
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@section{method}
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symmetricDifference, --
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Return the set of all items which are not elements of both this and strong::that::.
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@racketblock[
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a = Set[1, 2, 3]; b = Set[2, 3, 4, 5];
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symmetricDifference(a, b);
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a -- b // shorter syntax
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::
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]
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@section{method}
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isSubsetOf
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Returns true if all elements of this are also elements of strong::that::.
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@racketblock[
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a = Set[1, 2, 3, 4];
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Set[1, 2].isSubsetOf(a); // true
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Set[1, 5].isSubsetOf(a); // false
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::
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]
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@section{EXAMPLES}
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@racketblock[
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a = Set[1, 2, 3, 4];
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b = a.powerset; // set of all parts
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a.isSubsetOf(b); // false: no set is ever part of itself.
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b.asArray.reduce(\union) == a; // true parts may not contain other elements that original
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b.asArray.reduce(\difference).isEmpty; // true.
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::
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]
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@racketblock[
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// you can use Set to efficiently remove duplicates from an array:
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a = [1, 2, 3, 4, 3, 5, 5, 2, 2, 1];
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a.as(Set); // convert to set
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a.as(Set).as(Array); // and convert back
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::
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]
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