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<head><title>VisibleList _ List -- get some entries of a list</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="___Visible__List_sp_us_sp__List.html" title="get some entries of a list">VisibleList _ List</a></div>
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<div><h1>VisibleList _ List -- get some entries of a list</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>w_{i,j,...}</tt></div>
</dd></dl>
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</li>
<li><span>Operator: <a href="__us.html" title="a binary operator, used for subscripting and access to elements">_</a></span></li>
<li><div class="single">Inputs:<ul><li><span><tt>w</tt>, <span>a <a href="___Visible__List.html">visible list</a></span></span></li>
<li><span><tt>{i,j,...}</tt>, a list of integers to serve as indices</span></li>
</ul>
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</li>
<li><div class="single">Outputs:<ul><li><span><span>a <a href="___Visible__List.html">visible list</a></span>, the list of entries <tt>{w_i, w_j, ...}</tt></span></li>
</ul>
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</li>
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<div class="single"><h2>Description</h2>
<div><p>The entries of <tt>w</tt> are numbered starting with 0. If <tt>i</tt> is negative, then the <tt>i</tt>-th entry counting from the end is provided. If <tt>i</tt> is out of range, an error is signaled.</p>
<table class="examples"><tr><td><pre>i1 : w = {a,b,c,d,e,f,g,h}
o1 = {a, b, c, d, e, f, g, h}
o1 : List</pre>
</td></tr>
<tr><td><pre>i2 : w_{1,3,4}
o2 = {b, d, e}
o2 : List</pre>
</td></tr>
<tr><td><pre>i3 : w_{-1,-2,-3}
o3 = {h, g, f}
o3 : List</pre>
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<p/>
We can use this operation to compute composition of permutations represented as lists.<table class="examples"><tr><td><pre>i4 : {4,2,3,1,0} _ {2,1,3,4,0}
o4 = {3, 2, 1, 0, 4}
o4 : List</pre>
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<p/>
Remark: any subscripts that are sequences will have their elements spliced into the rest of the list.<table class="examples"><tr><td><pre>i5 : {a,b,c,d,e}_{2..4}
o5 = {c, d, e}
o5 : List</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_ranges_spand_sprepetitions.html" title="">ranges and repetitions</a></span></li>
<li><span><a href="___Visible__List_sp_us_sp__Z__Z.html" title="get element from list">VisibleList _ ZZ</a> -- get element from list</span></li>
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