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<head><title>positions(VisibleList,Function) -- which elements of a list satisfy a condition</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="_lists_spand_spsequences.html" title="">lists and sequences</a> > <a href="_positions_lp__Visible__List_cm__Function_rp.html" title="which elements of a list satisfy a condition">positions(VisibleList,Function)</a></div>
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<div><h1>positions(VisibleList,Function) -- which elements of a list satisfy a condition</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>positions(v,f)</tt></div>
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<li><span>Function: <a href="_positions_lp__Visible__List_cm__Function_rp.html" title="which elements of a list satisfy a condition">positions</a></span></li>
<li><div class="single">Inputs:<ul><li><span><tt>v</tt>, <span>a <a href="___Visible__List.html">visible list</a></span></span></li>
<li><span><tt>f</tt>, <span>a <a href="___Function.html">function</a></span>, which, when applied to an element of <tt>v</tt>, yields <a href="_true.html" title="">true</a> or <a href="_false.html" title="">false</a></span></li>
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<li><div class="single">Outputs:<ul><li><span><span>a <a href="___List.html">list</a></span>, the list of integers <tt>k</tt>, in ascending order, such that <tt>f v#k</tt> evaluates to <a href="_true.html" title="">true</a></span></li>
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<div class="single"><h2>Description</h2>
<div><table class="examples"><tr><td><pre>i1 : positions(100..110,isPrime)
o1 = {1, 3, 7, 9}
o1 : List</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_position.html" title="find first element of a list satisfying a condition">position</a> -- find first element of a list satisfying a condition</span></li>
<li><span><a href="_select.html" title="select from a list, hash table, or string">select</a> -- select from a list, hash table, or string</span></li>
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