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<head><title>class -- class of an object</title>
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<div><a href="index.html" title="">Macaulay2Doc</a> > <a href="___The_sp__Macaulay2_splanguage.html" title="">The Macaulay2 language</a> > <a href="_what_spa_spclass_spis.html" title="">what a class is</a> > <a href="_class.html" title="class of an object">class</a></div>
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<div><h1>class -- class of an object</h1>
<div class="single"><h2>Synopsis</h2>
<ul><li><div class="list"><dl class="element"><dt class="heading">Usage: </dt><dd class="value"><div><tt>class x</tt></div>
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<li><div class="single">Inputs:<ul><li><span><tt>x</tt>, <span>a <a href="___Thing.html">thing</a></span>, any Macaulay2 object</span></li>
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<li><div class="single">Outputs:<ul><li><span><span>a <a href="___Type.html">type</a></span>, the class of <tt>x</tt></span></li>
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<div class="single"><h2>Description</h2>
<div>Every object in Macaulay2 has a class, see <a href="_what_spa_spclass_spis.html" title="">what a class is</a> for more details.<table class="examples"><tr><td><pre>i1 : class {1,2,3}
o1 = List
o1 : Type</pre>
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<tr><td><pre>i2 : R = QQ[a..d]
o2 = R
o2 : PolynomialRing</pre>
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<tr><td><pre>i3 : class R
o3 = PolynomialRing
o3 : Type</pre>
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Use strict equality <tt>===</tt> to test the exact class of an object.<table class="examples"><tr><td><pre>i4 : class R === PolynomialRing
o4 = true</pre>
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<tr><td><pre>i5 : class R === Ring
o5 = false</pre>
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However, each PolynomialRing is a Ring, by inheritance, so a more useful test uses <a href="_instance.html" title="whether something has a certain type">instance</a>.<table class="examples"><tr><td><pre>i6 : instance(R,Ring)
o6 = true</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_instance.html" title="whether something has a certain type">instance</a> -- whether something has a certain type</span></li>
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