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<head><title>position -- find first element of a list satisfying 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="_position.html" title="find first element of a list satisfying a condition">position</a></div>
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<div><h1>position -- find first element of a list satisfying a condition</h1>
<div class="single"><h2>Synopsis</h2>
<ul><li><div class="single"><a href="_using_spfunctions_spwith_spoptional_spinputs.html">Optional inputs</a>:<ul><li><span><a href="_position_lp..._cm_sp__Reverse_sp_eq_gt_sp..._rp.html">Reverse => ...</a>, -- search the list in reverse order</span></li>
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<div class="single"><h2>Description</h2>
<div><tt>position(v,f)</tt> -- returns the index of the first element of <tt>v</tt> satisfying the condition <tt>f</tt>, or <a href="_null.html" title="the unique member of the empty class">null</a> if there is none.</div>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_positions_lp__Visible__List_cm__Function_rp.html" title="which elements of a list satisfy a condition">positions</a> -- which elements of a list satisfy a condition</span></li>
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<div class="waystouse"><h2>Ways to use <tt>position</tt> :</h2>
<ul><li>position(VisibleList,Function)</li>
<li><span><a href="_position_lp__Visible__List_cm__Visible__List_cm__Function_rp.html" title="find first element of a list satisfying a condition">position(VisibleList,VisibleList,Function)</a> -- find first element of a list satisfying a condition</span></li>
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