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<h1 class='fqn'><span class='in-band'>Macro <a href='index.html'>itertools</a>::<wbr><a class="macro" href=''>izip</a></span><span class='out-of-band'><span id='render-detail'>
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</span><a class='srclink' href='../src/itertools/lib.rs.html#247-269' title='goto source code'>[src]</a></span></h1>
<pre class="rust macro">
<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">izip</span> {
( @<span class="ident">closure</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">p</span>:<span class="ident">pat</span> <span class="op">=&gt;</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">tup</span>:<span class="ident">expr</span> ) <span class="op">=&gt;</span> { ... };
( @<span class="ident">closure</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">p</span>:<span class="ident">pat</span> <span class="op">=&gt;</span> ( $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">tup</span>:<span class="ident">tt</span>)<span class="op">*</span> ) , <span class="macro-nonterminal">$</span><span class="macro-nonterminal">_iter</span>:<span class="ident">expr</span> $( , <span class="macro-nonterminal">$</span><span class="macro-nonterminal">tail</span>:<span class="ident">expr</span> )<span class="op">*</span> ) <span class="op">=&gt;</span> { ... };
( <span class="macro-nonterminal">$</span><span class="macro-nonterminal">first</span>:<span class="ident">expr</span> $( , <span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">expr</span> )<span class="op">*</span> $(,)<span class="op">*</span> ) <span class="op">=&gt;</span> { ... };
}</pre>
<div class='docblock'><p>Create an iterator running multiple iterators in lockstep.</p>
<p>The <code>izip!</code> iterator yields elements until any subiterator
returns <code>None</code>.</p>
<p>This is a version of the standard <code>.zip()</code> that's supporting more than
two iterators. The iterator elment type is a tuple with one element
from each of the input iterators. Just like <code>.zip()</code>, the iteration stops
when the shortest of the inputs reaches its end.</p>
<p><strong>Note:</strong> The result of this macro is an iterator composed of
repeated <code>.zip()</code> and a <code>.map()</code>; it has an anonymous type.
Prefer this macro <code>izip!()</code> over <a href="fn.multizip.html"><code>multizip</code></a> for the performance benefits
of using the standard library <code>.zip()</code>.</p>
<pre class="rust rust-example-rendered">
<span class="attribute">#[<span class="ident">macro_use</span>]</span> <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">itertools</span>;
<span class="comment">// iterate over three sequences side-by-side</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">results</span> <span class="op">=</span> [<span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>];
<span class="kw">let</span> <span class="ident">inputs</span> <span class="op">=</span> [<span class="number">3</span>, <span class="number">7</span>, <span class="number">9</span>, <span class="number">6</span>];
<span class="kw">for</span> (<span class="ident">r</span>, <span class="ident">index</span>, <span class="ident">input</span>) <span class="kw">in</span> <span class="macro">izip</span><span class="macro">!</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">results</span>, <span class="number">0</span>..<span class="number">10</span>, <span class="kw-2">&amp;</span><span class="ident">inputs</span>) {
<span class="kw-2">*</span><span class="ident">r</span> <span class="op">=</span> <span class="ident">index</span> <span class="op">*</span> <span class="number">10</span> <span class="op">+</span> <span class="ident">input</span>;
}
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">results</span>, [<span class="number">0</span> <span class="op">+</span> <span class="number">3</span>, <span class="number">10</span> <span class="op">+</span> <span class="number">7</span>, <span class="number">29</span>, <span class="number">36</span>]);</pre>
<p><strong>Note:</strong> To enable the macros in this crate, use the <code>#[macro_use]</code>
attribute when importing the crate:</p>
<pre class="rust rust-example-rendered">
<span class="attribute">#[<span class="ident">macro_use</span>]</span> <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">itertools</span>;</pre>
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