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<head><title>variables -- The variables of a complex or co-complex.</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="_variables.html" title="The variables of a complex or co-complex.">variables</a></div>
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<div><h1>variables</h1>
<div>Valid names for symbols may be constructed using letters, digits, and the apostrophe, and should not begin with a digit.<table class="examples"><tr><td><pre>i1 : x
o1 = x
o1 : Symbol</pre>
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<tr><td><pre>i2 : q0r55
o2 = q0r55
o2 : Symbol</pre>
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<tr><td><pre>i3 : f'
o3 = f'
o3 : Symbol</pre>
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Some symbols have preassigned meanings and values. For example, symbols consisting of the letter <tt>o</tt> followed by a number are used to store output values.<table class="examples"><tr><td><pre>i4 : o2
o4 = q0r55
o4 : Symbol</pre>
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Other symbols refer to functions built into Macaulay2 that provide much of its functionality.<p/>
Sometimes, one wants the symbol, rather than the particular value it happens to have at the moment. For example after setting the value of <tt>x</tt> to 5, the value of the variable <tt>x</tt> is no longer the symbol <tt>x</tt>. Use <a href="_symbol.html" title="get a symbol">symbol</a> to recover the symbol itself.<table class="examples"><tr><td><pre>i5 : x=5
o5 = 5</pre>
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<tr><td><pre>i6 : x
o6 = 5</pre>
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<tr><td><pre>i7 : symbol x
o7 = x
o7 : Symbol</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_symbol.html" title="get a symbol">symbol</a> -- get a symbol</span></li>
<li><span><a href="_local.html" title="get a local symbol">local</a> -- get a local symbol</span></li>
<li><span><a href="_global.html" title="get a global symbol">global</a> -- get a global symbol</span></li>
<li><span><a href="_list__User__Symbols.html" title="display the user's symbols">listUserSymbols</a> -- display the user's symbols</span></li>
<li><span><a href="_clear__Output.html" title="forget output values">clearOutput</a> -- forget output values</span></li>
<li><span><a href="_clear__All.html" title="forget everything">clearAll</a> -- forget everything</span></li>
<li><span><a href="___Symbol.html" title="the class of all symbols">Symbol</a> -- the class of all symbols</span></li>
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<div><h3>Menu</h3>
<ul><li><span><a href="_valid_spnames.html" title="">valid names</a></span></li>
<li><span><a href="_assigning_spvalues.html" title="">assigning values</a></span></li>
<li><span><a href="_local_spvariables_spin_spa_spfile.html" title="">local variables in a file</a></span></li>
<li><span><a href="_viewing_spthe_spsymbols_spdefined_spso_spfar.html" title="">viewing the symbols defined so far</a></span></li>
<li><span><a href="_subscripted_spvariables.html" title="">subscripted variables</a></span></li>
<li><span><a href="_numbered_spvariables.html" title="">numbered variables</a></span></li>
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