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<head><title>select(HashTable,Function) -- select part of a hash table</title>
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<div><h1>select(HashTable,Function) -- select part of a hash table</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>select(v,f)</tt></div>
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<li><span>Function: <a href="_select.html" title="select from a list, hash table, or string">select</a></span></li>
<li><div class="single">Inputs:<ul><li><span><tt>v</tt>, <span>a <a href="___Hash__Table.html">hash table</a></span></span></li>
<li><span><tt>f</tt>, <span>a <a href="___Function.html">function</a></span>, returning either <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="___Hash__Table.html">hash table</a></span>, whose pairs are those key-value pairs <tt>(k,w)</tt> of the hash table <tt>v</tt> that yield <tt>true</tt> when the function <tt>f</tt> is applied to the value <tt>w</tt>.</span></li>
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<div class="single"><h2>Description</h2>
<div>The hash table <tt>v</tt> should be immutable: to scan the values in a mutable hash table, use <tt>scan(values x, f)</tt>.<table class="examples"><tr><td><pre>i1 : x = new HashTable from { x => 1, y => 2, z => 3 }
o1 = HashTable{x => 1}
y => 2
z => 3
o1 : HashTable</pre>
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<tr><td><pre>i2 : select(x,odd)
o2 = HashTable{x => 1}
z => 3
o2 : HashTable</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_partition.html" title="partition a set or list by values of a function">partition</a> -- partition a set or list by values of a function</span></li>
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