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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::pair&lt;T1,T2&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-utility.html">utility</a>&lrm; | <a href="cpp-utility-pair.html">pair</a></span></div>
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<td rowspan="142">(1)</td>
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<div><span class="mw-geshi cpp source-cpp">pair<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span> <span class="kw4">const</span> pair<span class="sy3">&amp;</span> other <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-until-cxx20">(C++20 &#21069;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> pair<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span> <span class="kw4">const</span> pair<span class="sy3">&amp;</span> other <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<td rowspan="142">(2)</td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> U1, <span class="kw1">class</span> U2 <span class="sy1">&gt;</span><br />
pair<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span> <span class="kw4">const</span> pair<span class="sy1">&lt;</span>U1,U2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> other <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span><br />
<span class="t-mark-rev t-until-cxx20">(C++20 &#21069;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> U1, <span class="kw1">class</span> U2 <span class="sy1">&gt;</span><br />
<span class="kw4">constexpr</span> pair<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span> <span class="kw4">const</span> pair<span class="sy1">&lt;</span>U1,U2<span class="sy1">&gt;</span><span class="sy3">&amp;</span> other <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<td rowspan="142">(3)</td>
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<div><span class="mw-geshi cpp source-cpp">pair<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span> pair<span class="sy3">&amp;&amp;</span> other <span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see below */</span><span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span><br />
<span class="t-mark-rev t-until-cxx20">(C++20 &#21069;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> pair<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span> pair<span class="sy3">&amp;&amp;</span> other <span class="br0">)</span> <span class="kw1">noexcept</span><span class="br0">(</span><span class="coMULTI">/* see below */</span><span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<td rowspan="142">(4)</td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> U1, <span class="kw1">class</span> U2 <span class="sy1">&gt;</span><br />
pair<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span> pair<span class="sy1">&lt;</span>U1,U2<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span> other <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td class="t-dcl-nopad"></td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span><br />
<span class="t-mark-rev t-until-cxx20">(C++20 &#21069;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> U1, <span class="kw1">class</span> U2 <span class="sy1">&gt;</span><br />
<span class="kw4">constexpr</span> pair<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span> pair<span class="sy1">&lt;</span>U1,U2<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span> other <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<p>&#26367;&#25442; <code>pair</code> &#30340;&#20869;&#23481;&#12290;</p>
<div class="t-li1"><span class="t-li">1)</span> &#22797;&#21046;&#36171;&#20540;&#36816;&#31639;&#31526;&#12290;&#20197; <code>other</code> &#20869;&#23481;&#30340;&#21103;&#26412;&#26367;&#25442;&#20869;&#23481;&#12290;
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<li>&#27492;&#36171;&#20540;&#36816;&#31639;&#31526;&#34987;&#38544;&#24335;&#22768;&#26126;&#12290;&#33509; <code>first_type</code> &#25110; <code>second_type</code> &#20043;&#19968;&#20026; const &#38480;&#23450;&#31867;&#22411;&#65292;&#25110;&#24341;&#29992;&#31867;&#22411;&#65292;&#25110;&#25317;&#26377;&#19981;&#21487;&#35775;&#38382;&#30340;&#22797;&#21046;&#36171;&#20540;&#36816;&#31639;&#31526;&#30340;&#31867;&#31867;&#22411;&#65292;&#25110;&#36825;&#31181;&#31867;&#30340;&#25968;&#32452;&#31867;&#22411;&#65292;&#21017;&#20351;&#29992;&#27492;&#36171;&#20540;&#36816;&#31639;&#31526;&#20196;&#31243;&#24207;&#20026;&#35884;&#26500;&#12290;</li>
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<td><span class="t-mark-rev t-until-cxx11">(C++11 &#21069;)</span></td>
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<li>&#33509; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_copy_assignable.html"><span class="kw550">std::<span class="me2">is_copy_assignable</span></span></a><span class="sy1">&lt;</span>first_type<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span></span></span> &#25110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_copy_assignable.html"><span class="kw550">std::<span class="me2">is_copy_assignable</span></span></a><span class="sy1">&lt;</span>second_type<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span></span></span> &#20043;&#19968;&#20026; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span> &#65292;&#21017;&#23450;&#20041;&#27492;&#37325;&#36733;&#20026;&#34987;&#21024;&#38500;&#12290;</li>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span></td>
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<div class="t-li1"><span class="t-li">2)</span> &#36171;&#20540; <code>other.first</code> &#32473; <code>first</code> &#65292; <code>other.second</code> &#32473; <code>second</code></div>
<div class="t-li1"><span class="t-li"></span> &#27492;&#37325;&#36733;&#20165;&#33509; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_assignable.html"><span class="kw544">std::<span class="me2">is_assignable</span></span></a><span class="sy1">&lt;</span>first_type<span class="sy3">&amp;</span>, <span class="kw4">const</span> U1<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span></span></span> &#19982; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_assignable.html"><span class="kw544">std::<span class="me2">is_assignable</span></span></a><span class="sy1">&lt;</span>second_type<span class="sy3">&amp;</span>, <span class="kw4">const</span> U2<span class="sy3">&amp;</span><span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span></span></span> &#22343;&#20026; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> &#25165;&#21442;&#19982;&#37325;&#36733;&#20915;&#35758;&#12290;</div>
<div class="t-li1"><span class="t-li">3)</span> &#31227;&#21160;&#36171;&#20540;&#36816;&#31639;&#31526;&#12290;&#29992;&#31227;&#21160;&#35821;&#20041;&#20197; <code>other</code> &#30340;&#20869;&#23481;&#26367;&#25442;&#20869;&#23481;&#12290;</div>
<div class="t-li1"><span class="t-li"></span> &#27492;&#37325;&#36733;&#20165;&#33509; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_move_assignable.html"><span class="kw556">std::<span class="me2">is_move_assignable</span></span></a><span class="sy1">&lt;</span>first_type<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span></span></span> &#19982; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_move_assignable.html"><span class="kw556">std::<span class="me2">is_move_assignable</span></span></a><span class="sy1">&lt;</span>second_type<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span></span></span> &#22343;&#20026; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> &#25165;&#21442;&#19982;&#37325;&#36733;&#20915;&#35758;&#12290;</div>
<div class="t-li1"><span class="t-li">4)</span> &#36171;&#20540; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-forward.html"><span class="kw1117">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>U1<span class="sy1">&gt;</span><span class="br0">(</span>p.<span class="me1">first</span><span class="br0">)</span></span></span> &#32473; <code>first</code> &#65292; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-forward.html"><span class="kw1117">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>U2<span class="sy1">&gt;</span><span class="br0">(</span>p.<span class="me1">second</span><span class="br0">)</span></span></span> &#32473; <code>second</code> &#12290;</div>
<div class="t-li1"><span class="t-li"></span> &#27492;&#37325;&#36733;&#20165;&#33509; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_assignable.html"><span class="kw544">std::<span class="me2">is_assignable</span></span></a><span class="sy1">&lt;</span>first_type<span class="sy3">&amp;</span>, U1<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span></span></span> &#19982; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_assignable.html"><span class="kw544">std::<span class="me2">is_assignable</span></span></a><span class="sy1">&lt;</span>second_type<span class="sy3">&amp;</span>, U2<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span></span></span> &#22343;&#20026; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> &#25165;&#21442;&#19982;&#37325;&#36733;&#20915;&#35758;&#12290;</div>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
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<td>other</td>
<td>-</td>
<td>&#26367;&#25442;&#27492; <code>pair</code> &#30340;&#20540;&#30340; <code>pair</code></td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span></p>
<h3><span class="mw-headline" id=".E5.BC.82.E5.B8.B8">&#24322;&#24120;</span></h3>
<div class="t-li1"><span class="t-li">1-2)</span> &#21487;&#33021;&#25243;&#20986;&#23454;&#29616;&#23450;&#20041;&#30340;&#24322;&#24120;&#12290;</div>
<div class="t-li1"><span class="t-li">3)</span>
<div class="t-noexcept-full"><a href="cpp-language-noexcept_spec.html"><tt>noexcept</tt></a> &#35828;&#26126;&#65306;&nbsp;&nbsp;
<div class="t-noexcept-box"><span class="t-cc"><span class="mw-geshi cpp source-cpp"><span class="kw1">noexcept</span><span class="br0">(</span><br /></span></span>
<p>&nbsp; &nbsp; <a href="cpp-types-is_move_assignable.html"><span class="kw560">std::<span class="me2">is_nothrow_move_assignable</span></span></a><span class="sy1">&lt;</span>T1<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span> <span class="sy3">&amp;&amp;</span><br />
&nbsp; &nbsp; <a href="cpp-types-is_move_assignable.html"><span class="kw560">std::<span class="me2">is_nothrow_move_assignable</span></span></a><span class="sy1">&lt;</span>T2<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><br /></p>
<span class="br0">)</span></div>
</div>
</div>
<div class="t-li1"><span class="t-li">4)</span> &#21487;&#33021;&#25243;&#20986;&#23454;&#29616;&#23450;&#20041;&#30340;&#24322;&#24120;&#12290;</div>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
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<td class="mbox-empty-cell"></td>
<td class="mbox-text" style="">&#26412;&#33410;&#26410;&#23436;&#25104;<br />
&#21407;&#22240;&#65306;&#26242;&#26080;&#31034;&#20363;</td>
</tr>
</table>
<h3><span class="mw-headline" id=".E7.BC.BA.E9.99.B7.E6.8A.A5.E5.91.8A">&#32570;&#38519;&#25253;&#21578;</span></h3>
<p>&#19979;&#21015;&#26356;&#25913;&#34892;&#20026;&#30340;&#32570;&#38519;&#25253;&#21578;&#36861;&#28335;&#22320;&#24212;&#29992;&#20110;&#20197;&#21069;&#20986;&#29256;&#30340; C++ &#26631;&#20934;&#12290;</p>
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<th>DR</th>
<th>&#24212;&#29992;&#20110;</th>
<th>&#20986;&#29256;&#26102;&#30340;&#34892;&#20026;</th>
<th>&#27491;&#30830;&#34892;&#20026;</th>
</tr>
<tr>
<td><a rel="nofollow" class="external text" href="https://cplusplus.github.io/LWG/issue2729">LWG 2729</a></td>
<td>C++11</td>
<td><code>pair::operator=</code> &#26410;&#34987;&#32422;&#26463;&#24182;&#21487;&#33021;&#23548;&#33268;&#19981;&#24517;&#35201;&#30340;&#26410;&#23450;&#20041;&#34892;&#20026;</td>
<td>&#24050;&#32422;&#26463;</td>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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