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<title>std::unordered_map&lt;Key,T,Hash,KeyEqual,Allocator&gt;::operator[]</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::unordered_map&lt;Key,T,Hash,KeyEqual,Allocator&gt;::</span>operator[]</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-container.html">container</a>&lrm; | <a href="cpp-container-unordered_map.html">unordered map</a></span></div>
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<div><span class="mw-geshi cpp source-cpp">T<span class="sy3">&amp;</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span> <span class="kw4">const</span> Key<span class="sy3">&amp;</span> key <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(1)</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span></td>
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<div><span class="mw-geshi cpp source-cpp">T<span class="sy3">&amp;</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span> Key<span class="sy3">&amp;&amp;</span> key <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(2)</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span></td>
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<p>&#36820;&#22238;&#21040;&#26144;&#23556;&#21040;&#31561;&#20110; <code>key</code> &#30340;&#38190;&#30340;&#20540;&#30340;&#24341;&#29992;&#65292;&#33509;&#36825;&#31181;&#38190;&#19981;&#23384;&#22312;&#21017;&#36827;&#34892;&#25554;&#20837;&#12290;</p>
<div class="t-li1"><span class="t-li">1)</span> &#33509;&#38190;&#19981;&#23384;&#22312;&#65292;&#21017;&#25554;&#20837;&#20174; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-piecewise_construct.html"><span class="kw1106">std::<span class="me2">piecewise_construct</span></span></a>, <a href="cpp-utility-tuple-forward_as_tuple.html"><span class="kw1114">std::<span class="me2">forward_as_tuple</span></span></a><span class="br0">(</span>key<span class="br0">)</span>, <a href="cpp-utility-tuple.html"><span class="kw1098">std::<span class="me2">tuple</span></span></a><span class="sy1">&lt;&gt;</span><span class="br0">(</span><span class="br0">)</span></span></span> &#21407;&#20301;&#26500;&#36896;&#30340; <code>value_type</code> &#23545;&#35937;&#12290;<span class="t-rev-inl t-since-cxx17"><span>&#27492;&#20989;&#25968;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">return</span> this<span class="sy2">-</span><span class="sy1">&gt;</span>try_emplace<span class="br0">(</span>key<span class="br0">)</span>.<span class="me1">first</span><span class="sy2">-</span><span class="sy1">&gt;</span>second<span class="sy4">;</span></span></span> &#12290;</span> <span><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></span></span><br />
&#20351;&#29992;&#40664;&#35748;&#20998;&#37197;&#22120;&#26102;&#65292;&#36825;&#23548;&#33268;&#20174; <code>key</code> &#22797;&#21046;&#26500;&#36896;&#20851;&#38190;&#65292;&#24182;<a href="cpp-language-value_initialization.html">&#20540;&#21021;&#22987;&#21270;</a>&#34987;&#26144;&#23556;&#20540;&#12290;
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<td colspan="3">-
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<code>value_type</code> &#24517;&#39035;&#20174; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-piecewise_construct.html"><span class="kw1106">std::<span class="me2">piecewise_construct</span></span></a>, <a href="cpp-utility-tuple-forward_as_tuple.html"><span class="kw1114">std::<span class="me2">forward_as_tuple</span></span></a><span class="br0">(</span>key<span class="br0">)</span>, <a href="cpp-utility-tuple.html"><span class="kw1098">std::<span class="me2">tuple</span></span></a><span class="sy1">&lt;&gt;</span><span class="br0">(</span><span class="br0">)</span></span></span> <a href="cpp-named_req-EmplaceConstructible.html"><span style="font-style:italic">&#21487;&#23601;&#20301;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(EmplaceConstructible)</span></a> &#12290;&#20351;&#29992;&#40664;&#35748;&#20998;&#37197;&#22120;&#26102;&#65292;&#36825;&#34920;&#26126; <code>key_type</code> &#24517;&#39035;<a href="cpp-named_req-CopyConstructible.html"><span style="font-style:italic">&#21487;&#22797;&#21046;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(CopyConstructible)</span></a> &#32780; <code>mapped_type</code> &#24517;&#39035;<a href="cpp-named_req-DefaultConstructible.html"><span style="font-style:italic">&#21487;&#40664;&#35748;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(DefaultConstructible)</span></a> &#12290;</td>
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<div class="t-li1"><span class="t-li">2)</span> &#33509;&#38190;&#19981;&#23384;&#22312;&#65292;&#21017;&#25554;&#20837;&#20174; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-piecewise_construct.html"><span class="kw1106">std::<span class="me2">piecewise_construct</span></span></a>, <a href="cpp-utility-tuple-forward_as_tuple.html"><span class="kw1114">std::<span class="me2">forward_as_tuple</span></span></a><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>key<span class="br0">)</span><span class="br0">)</span>, <a href="cpp-utility-tuple.html"><span class="kw1098">std::<span class="me2">tuple</span></span></a><span class="sy1">&lt;&gt;</span><span class="br0">(</span><span class="br0">)</span></span></span> &#21407;&#20301;&#26500;&#36896;&#30340; <code>value_type</code> &#23545;&#35937;&#12290;<span class="t-rev-inl t-since-cxx17"><span>&#27492;&#20989;&#25968;&#31561;&#20215;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">return</span> this<span class="sy2">-</span><span class="sy1">&gt;</span>try_emplace<span class="br0">(</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>key<span class="br0">)</span><span class="br0">)</span>.<span class="me1">first</span><span class="sy2">-</span><span class="sy1">&gt;</span>second<span class="sy4">;</span></span></span> &#12290;</span> <span><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></span></span><br />
&#20351;&#29992;&#40664;&#35748;&#20998;&#37197;&#22120;&#26102;&#65292;&#36825;&#23548;&#33268;&#20174; <code>key</code> &#31227;&#21160;&#26500;&#36896;&#20851;&#38190;&#65292;&#24182;<a href="cpp-language-value_initialization.html">&#20540;&#21021;&#22987;&#21270;</a>&#34987;&#26144;&#23556;&#20540;&#12290;
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<td colspan="3">-
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<code>value_type</code> &#24517;&#39035;&#20174; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-piecewise_construct.html"><span class="kw1106">std::<span class="me2">piecewise_construct</span></span></a>, <a href="cpp-utility-tuple-forward_as_tuple.html"><span class="kw1114">std::<span class="me2">forward_as_tuple</span></span></a><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>key<span class="br0">)</span><span class="br0">)</span>, <a href="cpp-utility-tuple.html"><span class="kw1098">std::<span class="me2">tuple</span></span></a><span class="sy1">&lt;&gt;</span><span class="br0">(</span><span class="br0">)</span></span></span> <a href="cpp-named_req-EmplaceConstructible.html"><span style="font-style:italic">&#21487;&#23601;&#20301;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(EmplaceConstructible)</span></a> &#12290;&#20351;&#29992;&#40664;&#35748;&#20998;&#37197;&#22120;&#26102;&#65292;&#36825;&#34920;&#26126; <code>key_type</code> &#24517;&#39035;&#20026;<a href="cpp-named_req-MoveConstructible.html"><span style="font-style:italic">&#21487;&#31227;&#21160;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(MoveConstructible)</span></a> &#32780; <code>mapped_type</code> &#24517;&#39035;&#20026;<a href="cpp-named_req-DefaultConstructible.html"><span style="font-style:italic">&#21487;&#40664;&#35748;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(DefaultConstructible)</span></a> &#12290;</td>
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<p>&#33509;&#25554;&#20837;&#21457;&#29983;&#19988;&#23548;&#33268;&#23481;&#22120;&#30340;&#37325;&#21704;&#24076;&#65292;&#21017;&#25152;&#26377;&#36845;&#20195;&#22120;&#34987;&#38750;&#27861;&#21270;&#12290;&#21542;&#21017;&#36845;&#20195;&#22120;&#19981;&#21463;&#24433;&#21709;&#12290;&#37325;&#21704;&#24076;&#20165;&#33509;&#26032;&#20803;&#32032;&#25968;&#37327;&#22823;&#20110; <span class="t-c"><span class="mw-geshi cpp source-cpp">max_load_factor<span class="br0">(</span><span class="br0">)</span><span class="sy2">*</span>bucket_count<span class="br0">(</span><span class="br0">)</span></span></span> &#25165;&#21457;&#29983;&#12290;</p>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
<table class="t-par-begin">
<tr class="t-par">
<td>key</td>
<td>-</td>
<td>&#35201;&#23547;&#25214;&#30340;&#20803;&#32032;&#38190;</td>
</tr>
</table>
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#33509;&#19981;&#23384;&#22312;&#25317;&#26377;&#20851;&#38190; <code>key</code> &#30340;&#20803;&#32032;&#65292;&#21017;&#20026;&#21040;&#26032;&#20803;&#32032;&#34987;&#26144;&#23556;&#20540;&#30340;&#24341;&#29992;&#12290;&#21542;&#21017;&#20026;&#21040;&#26082;&#23384;&#30340;&#20851;&#38190;&#31561;&#20215;&#20110; <code>key</code> &#30340;&#20803;&#32032;&#30340;&#34987;&#26144;&#23556;&#20540;&#30340;&#24341;&#29992;&#12290;</p>
<h3><span class="mw-headline" id=".E5.BC.82.E5.B8.B8">&#24322;&#24120;</span></h3>
<p>&#33509;&#20219;&#20309;&#25805;&#20316;&#25243;&#20986;&#24322;&#24120;&#65292;&#21017;&#25554;&#20837;&#26080;&#25928;&#26524;&#12290;</p>
<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">&#22797;&#26434;&#24230;</span></h3>
<p>&#24179;&#22343;&#24773;&#20917;&#65306;&#24120;&#25968;&#65292;&#26368;&#22351;&#24773;&#20917;&#65306;&#19982;&#22823;&#23567;&#25104;&#32447;&#24615;&#12290;</p>
<h3><span class="mw-headline" id=".E6.B3.A8.E8.A7.A3">&#27880;&#35299;</span></h3>
<p>&#20986;&#29256;&#30340; C++11 &#21644; C++14 &#26631;&#20934;&#20013;&#65292;&#25351;&#23450;&#27492;&#20989;&#25968;&#35201;&#27714; <code>mapped_type</code> &#20026;<a href="cpp-named_req-DefaultInsertable.html"><span style="font-style:italic">&#21487;&#40664;&#35748;&#25554;&#20837;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(DefaultInsertable)</span></a> &#19988; <code>key_type</code> &#20026;<a href="cpp-named_req-CopyInsertable.html"><span style="font-style:italic">&#21487;&#22797;&#21046;&#25554;&#20837;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(CopyInsertable)</span></a> &#25110;<a href="cpp-named_req-MoveInsertable.html"><span style="font-style:italic">&#21487;&#31227;&#21160;&#25554;&#20837;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(MoveInsertable)</span></a> &#21040; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> &#12290;&#27492;&#35268;&#23450;&#26377;&#32570;&#38519;&#24182;&#20026; <a rel="nofollow" class="external text" href="https://cplusplus.github.io/LWG/issue2469">LWG &#38382;&#39064; 2469</a> &#25152;&#20462;&#22797;&#65292;&#32780;&#19978;&#38754;&#30340;&#25551;&#36848;&#21512;&#24182;&#20102;&#35813;&#38382;&#39064;&#30340;&#35299;&#20915;&#26041;&#26696;&#12290;</p>
<p>&#28982;&#32780;&#65292;&#24050;&#30693;&#19968;&#20010;&#23454;&#29616;&#65288; libc++ &#65289;&#36890;&#36807;&#20108;&#20010;&#20998;&#31163;&#30340;&#20998;&#37197;&#22120; <code>construct()</code> &#35843;&#29992;&#26500;&#36896; <code>key_type</code> &#21644; <code>mapped_type</code> &#23545;&#35937;&#65292;&#21487;&#35748;&#20026;&#22914;&#21457;&#24067;&#26102;&#30340;&#26631;&#20934;&#25152;&#35201;&#27714;&#65292;&#32780;&#38750;&#21407;&#20301;&#26500;&#36896; <code>value_type</code> &#23545;&#35937;&#12290;</p>
<p><code>operator[]</code> &#38750; const &#65292;&#22240;&#20026;&#33509;&#19981;&#20851;&#38190;&#19981;&#23384;&#22312;&#21017;&#23427;&#25554;&#20837;&#20851;&#38190;&#12290;&#33509;&#27492;&#34892;&#20026;&#38750;&#25152;&#27442;&#25110;&#23481;&#22120;&#20026; <code>const</code> &#65292;&#21017;&#21487;&#29992; <a href="cpp-container-unordered_map-at.html"><code>at()</code></a> &#12290;</p>
<table class="t-rev-begin">
<tr class="t-rev t-since-cxx17">
<td>
<p><a href="cpp-container-unordered_map-insert_or_assign.html"><code>insert_or_assign()</code></a> &#36820;&#22238;&#30340;&#20449;&#24687;&#22810;&#20110; <code>operator[]</code> &#65292;&#32780;&#19988;&#19981;&#35201;&#27714; <code>mapped_type</code> &#21487;&#40664;&#35748;&#26500;&#36896;&#12290;</p>
</td>
<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></td>
</tr>
</table>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
<div class="t-example">
<div class="t-example-live-link"></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;string&gt;</span>
<span class="co2">#include &lt;vector&gt;</span>
<span class="co2">#include &lt;unordered_map&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<a href="cpp-container-unordered_map.html"><span class="kw1293">std::<span class="me2">unordered_map</span></span></a><span class="sy1">&lt;</span><span class="kw4">char</span>, <span class="kw4">int</span><span class="sy1">&gt;</span> letter_counts <span class="br0">{</span><span class="br0">{</span><span class="st0">&#39;a&#39;</span>, <span class="nu0">27</span><span class="br0">}</span>, <span class="br0">{</span><span class="st0">&#39;b&#39;</span>, <span class="nu0">3</span><span class="br0">}</span>, <span class="br0">{</span><span class="st0">&#39;c&#39;</span>, <span class="nu0">1</span><span class="br0">}</span><span class="br0">}</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;initially:<span class="es1">\n</span>&quot;</span><span class="sy4">;</span>
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> <span class="sy3">&amp;</span>pair <span class="sy4">:</span> letter_counts<span class="br0">)</span> <span class="br0">{</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> pair.<span class="me1">first</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;: &quot;</span> <span class="sy1">&lt;&lt;</span> pair.<span class="me1">second</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="br0">}</span>
letter_counts<span class="br0">[</span><span class="st0">&#39;b&#39;</span><span class="br0">]</span> <span class="sy1">=</span> <span class="nu0">42</span><span class="sy4">;</span> <span class="co1">// &#26356;&#26032;&#26082;&#23384;&#20540;</span>
letter_counts<span class="br0">[</span><span class="st0">&#39;x&#39;</span><span class="br0">]</span> <span class="sy1">=</span> <span class="nu0">9</span><span class="sy4">;</span> <span class="co1">// &#25554;&#20837;&#26032;&#20540;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;after modifications:<span class="es1">\n</span>&quot;</span><span class="sy4">;</span>
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> <span class="sy3">&amp;</span>pair <span class="sy4">:</span> letter_counts<span class="br0">)</span> <span class="br0">{</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> pair.<span class="me1">first</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;: &quot;</span> <span class="sy1">&lt;&lt;</span> pair.<span class="me1">second</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="br0">}</span>
<span class="co1">// &#32479;&#35745;&#27599;&#20010;&#35789;&#30340;&#20986;&#29616;&#25968;</span>
<span class="co1">// &#65288;&#39318;&#27425;&#35843;&#29992; operator[] &#20197;&#38646;&#21021;&#22987;&#21270;&#35745;&#25968;&#22120;&#65289;</span>
<a href="cpp-container-unordered_map.html"><span class="kw1293">std::<span class="me2">unordered_map</span></span></a><span class="sy1">&lt;</span><a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a>, size_t<span class="sy1">&gt;</span> word_map<span class="sy4">;</span>
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> <span class="sy3">&amp;</span>w <span class="sy4">:</span> <span class="br0">{</span> <span class="st0">&quot;this&quot;</span>, <span class="st0">&quot;sentence&quot;</span>, <span class="st0">&quot;is&quot;</span>, <span class="st0">&quot;not&quot;</span>, <span class="st0">&quot;a&quot;</span>, <span class="st0">&quot;sentence&quot;</span>,
<span class="st0">&quot;this&quot;</span>, <span class="st0">&quot;sentence&quot;</span>, <span class="st0">&quot;is&quot;</span>, <span class="st0">&quot;a&quot;</span>, <span class="st0">&quot;hoax&quot;</span><span class="br0">}</span><span class="br0">)</span> <span class="br0">{</span>
<span class="sy2">++</span>word_map<span class="br0">[</span>w<span class="br0">]</span><span class="sy4">;</span>
<span class="br0">}</span>
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> <span class="sy3">&amp;</span>pair <span class="sy4">:</span> word_map<span class="br0">)</span> <span class="br0">{</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> pair.<span class="me1">second</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot; occurrences of word &#39;&quot;</span> <span class="sy1">&lt;&lt;</span> pair.<span class="me1">first</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;&#39;<span class="es1">\n</span>&quot;</span><span class="sy4">;</span>
<span class="br0">}</span>
<span class="br0">}</span></pre></div>
</div>
<p>&#21487;&#33021;&#30340;&#36755;&#20986;&#65306;</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="text source-text">
<pre class="de1">initially:
a: 27
b: 3
c: 1
after modifications:
a: 27
b: 42
c: 1
x: 9
2 occurrences of word &#39;a&#39;
1 occurrences of word &#39;hoax&#39;
2 occurrences of word &#39;is&#39;
1 occurrences of word &#39;not&#39;
3 occurrences of word &#39;sentence&#39;
2 occurrences of word &#39;this&#39;</pre></div>
</div>
</div>
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
<table class="t-dsc-begin">
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<td>
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<div><a href="cpp-container-unordered_map-at.html"><span class="t-lines"><span>at</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
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</td>
<td>&#35775;&#38382;&#25351;&#23450;&#30340;&#20803;&#32032;&#65292;&#21516;&#26102;&#36827;&#34892;&#36234;&#30028;&#26816;&#26597;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
</tr>
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="cpp-container-unordered_map-insert_or_assign.html"><span class="t-lines"><span>insert_or_assign</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div>
</div>
</td>
<td>&#25554;&#20837;&#20803;&#32032;&#65292;&#25110;&#33509;&#38190;&#24050;&#23384;&#22312;&#21017;&#36171;&#20540;&#32473;&#24403;&#21069;&#20803;&#32032;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
</tr>
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="cpp-container-unordered_map-try_emplace.html"><span class="t-lines"><span>try_emplace</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div>
</div>
</td>
<td>&#33509;&#38190;&#19981;&#23384;&#22312;&#21017;&#21407;&#20301;&#25554;&#20837;&#65292;&#33509;&#38190;&#23384;&#22312;&#21017;&#19981;&#20570;&#20219;&#20309;&#20107;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
</tr>
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