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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Chapter 10. Mängdlära i GEL</title><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot"><link rel="home" href="index.html" title="Handbok för Genius"><link rel="up" href="index.html" title="Handbok för Genius"><link rel="prev" href="ch09.html" title="Chapter 9. Polynom i GEL"><link rel="next" href="ch11.html" title="Chapter 11. Lista över GEL-funktioner"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 10. Mängdlära i GEL</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch09.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ch11.html">Next</a></td></tr></table><hr></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="genius-gel-settheory"></a>Chapter 10. Mängdlära i GEL</h1></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="sect1"><a href="ch10.html#genius-gel-sets-using">Använda mängder</a></span></dt></dl></div><p>Genius har viss grundläggande mängdteoretisk funktionalitet inbyggd. För närvarande är en mängd bara en vektor (eller en matris). Varje distinkt objekt behandlas som ett eget element.</p><div class="sect1"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="genius-gel-sets-using"></a>Använda mängder</h2></div></div></div><p>Precis som vektorer kan objekt i mängder inkludera tal, strängar, <code class="constant">null</code>, matriser och vektorer. Det planeras att i framtiden ha en enkom typ för mängder, snarare än att använda vektorer. Observera att flyttal skiljer sig åt från heltal även om de verkar vara lika. Det vill säga Genius behandlar <code class="constant">0</code> och <code class="constant">0.0</code> som två olika element. <code class="constant">null</code> behandlas som en tom mängd.</p><p lang="en">
To build a set out of a vector, use the
<a class="link" href="ch11s16.html#gel-function-MakeSet"><code class="function">MakeSet</code></a> function.
Currently, it will just return a new vector where every element is unique.
</p><pre lang="en" class="screen"><code class="prompt">genius> </code><strong class="userinput"><code>MakeSet([1,2,2,3])</code></strong>
= [1, 2, 3]
</pre><p lang="en">
</p><p lang="en">
Similarly there are functions
<a class="link" href="ch11s16.html#gel-function-Union"><code class="function">Union</code></a>,
<a class="link" href="ch11s16.html#gel-function-Intersection"><code class="function">Intersection</code></a>,
<a class="link" href="ch11s16.html#gel-function-SetMinus"><code class="function">SetMinus</code></a>, which
are rather self explanatory. For example:
</p><pre lang="en" class="screen"><code class="prompt">genius> </code><strong class="userinput"><code>Union([1,2,3], [1,2,4])</code></strong>
= [1, 2, 4, 3]
</pre><p lang="en">
Note that no order is guaranteed for the return values. If you wish to sort the vector you
should use the
<a class="link" href="ch11s08.html#gel-function-SortVector"><code class="function">SortVector</code></a> function.
</p><p lang="en">
For testing membership, there are functions
<a class="link" href="ch11s16.html#gel-function-IsIn"><code class="function">IsIn</code></a> and
<a class="link" href="ch11s16.html#gel-function-IsSubset"><code class="function">IsSubset</code></a>,
which return a boolean value. For example:
</p><pre lang="en" class="screen"><code class="prompt">genius> </code><strong class="userinput"><code>IsIn (1, [0,1,2])</code></strong>
= true
</pre><p lang="en">
The input <strong class="userinput"><code>IsIn(x,X)</code></strong> is equivalent to
<strong class="userinput"><code>IsSubset([x],X)</code></strong>. Note that since the empty set is a subset
of every set, <strong class="userinput"><code>IsSubset(null,X)</code></strong> is always true.
</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch09.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="ch11.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 9. Polynom i GEL </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 11. Lista över GEL-funktioner</td></tr></table></div></body></html>
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