blocks|key|1277458|text|外壳，4字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1277459|εṠ-u|code-block|syntax|javascript|1277460|在网上试试！|unstyled|1277461|解释|1277462|εṠ-u++Implicit+input.
+++u++Unique+elements.
+Ṡ-+++Delete+them+from+input,+counting+multiplicities.
ε+++++Is+the+result+a+singleton+list?|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/barbuz/Husk|1|https://tio.run/##yygtzv6vkKtR/KipsUjz0Lb/57Y@3LlAt/T////RhjqGsVxA0ghKm@kY65gAobmOJZBvABaDqQFBIyjLCMwyArNgokZgvaaxAA^0|0|2|0|0|0|0|6|1|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|13|8|@]|9|@$A|14|B|15|1|16]]|C|$]]|$1|L|3|M|5|6|7|17|8|@]|9|@]|C|$]]|$1|N|3|O|5|F|7|18|8|@]|9|@]|C|$G|H]]]|P|$Q|$5|R|S|T|C|$U|V]]|W|$5|R|S|T|C|$U|X]]]]

<h1><a href="https://github.com/barbuz/Husk" rel="noreferrer">Husk</a>, 4 bytes</h1>

<pre><code>εṠ-u
</code></pre>

<p><a href="https://tio.run/##yygtzv6vkKtR/KipsUjz0Lb/57Y@3LlAt/T////RhjqGsVxA0ghKm@kY65gAobmOJZBvABaDqQFBIyjLCMwyArNgokZgvaaxAA" rel="noreferrer" title="Husk – Try It Online">Try it online!</a></p>

<h2>Explanation</h2>

<pre><code>εṠ-u  Implicit input.
   u  Unique elements.
 Ṡ-   Delete them from input, counting multiplicities.
ε     Is the result a singleton list?
</code></pre>


blocks|key|140461|text|哈斯克尔，34字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|140462|f+x=[1%7Ca<-x,b<-x,a==b]==1:1:(1<$x)|code-block|syntax|javascript|140463|基于在网上试试！的H.PWiz的回答。|unstyled|entityMap|0|LINK|mutability|MUTABLE|url|https://www.haskell.org/|1|https://tio.run/##y0gszk7Nyfn/P02hwjbasCbRRrdCJwlEJNraJsXa2hpaGVppGNqoVGj@z03MzFOwVUjJ51IAgoKizLwSBRWFNIVoQx3DWEwxI6yiZjrGOiZAaK5jiSFrgEU9drNB0AiruBEWcSOwOHYdRmD3mMZy/QcA|2|https://codegolf.stackexchange.com/a/145064/56433^0|0|4|0|0|0|2|6|1|9|9|2^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|11|8|@]|9|@$A|12|B|13|1|14]|$A|15|B|16|1|17]]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]|U|$5|N|O|P|C|$Q|V]]]]

<h1><a href="https://www.haskell.org/" rel="noreferrer">Haskell</a>, 34 bytes</h1>



<pre class="lang-hs prettyprint-override"><code>f x=[1|a&lt;-x,b&lt;-x,a==b]==1:1:(1&lt;$x)
</code></pre>

<p><a href="https://tio.run/##y0gszk7Nyfn/P02hwjbasCbRRrdCJwlEJNraJsXa2hpaGVppGNqoVGj@z03MzFOwVUjJ51IAgoKizLwSBRWFNIVoQx3DWEwxI6yiZjrGOiZAaK5jiSFrgEU9drNB0AiruBEWcSOwOHYdRmD3mMZy/QcA" rel="noreferrer" title="Haskell – Try It Online">Try it online!</a> Based on <a href="https://codegolf.stackexchange.com/a/145064/56433">H.PWiz' answer</a>.</p>


blocks|key|1277402|text|JavaScript+(ES6)，30字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|1277403|a=>new+Set(a).size==a.length-1|code-block|syntax|javascript|1277404|在网上试试|unstyled|offset|length|entityMap|0|LINK|mutability|MUTABLE|url|https://tio.run/##y0osSyxOLsosKNHNy09J/Z@cn1ecn5Oql5OfrqHxP9HWLi@1XCE4tUQjUVOvOLMq1dY2US8nNS@9JEPX8L@mRrShjpmOsY4JEJrrWMZqav4HAA^0|0|0|0|5|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|I|7|U|8|@]|9|@$J|V|K|W|1|X]]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

<h1>JavaScript (ES6), 30 bytes</h1>
<pre><code>a=&gt;new Set(a).size==a.length-1
</code></pre>
<p><a href="https://tio.run/##y0osSyxOLsosKNHNy09J/Z@cn1ecn5Oql5OfrqHxP9HWLi@1XCE4tUQjUVOvOLMq1dY2US8nNS@9JEPX8L@mRrShjpmOsY4JEJrrWMZqav4HAA" rel="noreferrer">Try it online</a></p>


blocks|key|1277233|text|八度，25字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1277234|这并不是使用group或unique方法，而是使用所有可能的比较的“笛卡尔积”。|unstyled|style|CODE|1277235|@(x)nnz(triu(x==x',1))==1|code-block|syntax|javascript|1277236|解释|1277237|+++++++++++++x==x'++++++++%25create+a+matrix+where+the+entry+at+(i,j)+compares+whether+x(i)+==+x(ju)
++++++++triu(x==x',1)+++++%25only+consider+the+strict+upper+triangular+matrix
++++nnz(triu(x==x',1))++++%25count+the+number+of+nonzero+entries
@(x)nnz(triu(x==x',1))==1+%25check+whether+this+number+is+actually+1|1277238|在网上试试！|1277239|因为没有卷积程序是不完整的(谢谢@LuisMendo修复了一个错误)：|1277240|八度，40字节|1277241|@(x)nnz(~conv(sort(x),-1:2:1,'same'))==1|1277242|entityMap|0|LINK|mutability|MUTABLE|url|https://www.gnu.org/software/octave/|1|https://tio.run/##y08uSSxL/f/fQaNCMy@vSqOkKLNUo8LWtkJdx1BT09bW8H9iXrFGtKGOoY6xjomOaazmfwA|2|3|https://tio.run/##y08uSSxL/f/fQaNCMy@vSqMuOT@vTKM4v6gEKKCja2hlZGWoo16cmJuqrqlpa2v4PzGvWCPaUMdQx1jHRMc0VvM/AA^0|0|2|0|0|6|5|C|6|0|0|0|0|0|6|1|0|0|0|2|2|0|0|0|6|3^^$0|@$1|2|3|4|5|6|7|1C|8|@]|9|@$A|1D|B|1E|1|1F]]|C|$]]|$1|D|3|E|5|F|7|1G|8|@$A|1H|B|1I|G|H]|$A|1J|B|1K|G|H]]|9|@]|C|$]]|$1|I|3|J|5|K|7|1L|8|@]|9|@]|C|$L|M]]|$1|N|3|O|5|6|7|1M|8|@]|9|@]|C|$]]|$1|P|3|Q|5|K|7|1N|8|@]|9|@]|C|$L|M]]|$1|R|3|S|5|F|7|1O|8|@]|9|@$A|1P|B|1Q|1|1R]]|C|$]]|$1|T|3|U|5|F|7|1S|8|@]|9|@]|C|$]]|$1|V|3|W|5|6|7|1T|8|@]|9|@$A|1U|B|1V|1|1W]]|C|$]]|$1|X|3|Y|5|K|7|1X|8|@]|9|@]|C|$L|M]]|$1|Z|3|S|5|F|7|1Y|8|@]|9|@$A|1Z|B|20|1|21]]|C|$]]]|10|$11|$5|12|13|14|C|$15|16]]|17|$5|12|13|14|C|$15|18]]|19|$5|12|13|14|C|$15|16]]|1A|$5|12|13|14|C|$15|1B]]]]

<h1><a href="https://www.gnu.org/software/octave/" rel="nofollow noreferrer">Octave</a>, 25 bytes</h1>

<p>This is not using a <code>group</code> or <code>unique</code> approach as many of the other answers, but rather the "cartesian product" of all possible comparisions.</p>



<pre class="lang-matlab prettyprint-override"><code>@(x)nnz(triu(x==x',1))==1
</code></pre>

<h3>Explanation</h3>

<pre class="lang-matlab prettyprint-override"><code>             x==x'        %create a matrix where the entry at (i,j) compares whether x(i) == x(ju)
        triu(x==x',1)     %only consider the strict upper triangular matrix
    nnz(triu(x==x',1))    %count the number of nonzero entries
@(x)nnz(triu(x==x',1))==1 %check whether this number is actually 1
</code></pre>

<p><a href="https://tio.run/##y08uSSxL/f/fQaNCMy@vSqOkKLNUo8LWtkJdx1BT09bW8H9iXrFGtKGOoY6xjomOaazmfwA" rel="nofollow noreferrer" title="Octave – Try It Online">Try it online!</a></p>

<p>And because no program would be complete without a convolution (thanks @LuisMendo for fixing a mistake):</p>

<h1><a href="https://www.gnu.org/software/octave/" rel="nofollow noreferrer">Octave</a>, 40 bytes</h1>



<pre class="lang-matlab prettyprint-override"><code>@(x)nnz(~conv(sort(x),-1:2:1,'same'))==1
</code></pre>

<p><a href="https://tio.run/##y08uSSxL/f/fQaNCMy@vSqMuOT@vTKM4v6gEKKCja2hlZGWoo16cmJuqrqlpa2v4PzGvWCPaUMdQx1jHRMc0VvM/AA" rel="nofollow noreferrer" title="Octave – Try It Online">Try it online!</a></p>


blocks|key|1277364|text|咄咄逼人，8字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1277365|检查len(set(list))+==+len(list)-1是否：|unstyled|style|CODE|1277366|LtvuL%5E=#|code-block|syntax|javascript|1277367|解释：|1277368|+++++++\+Implicit:+Put+all+input+on+stack
Ltv++++\+Get+the+stack+length+-+1,+save+in+auxiliary+stack
u++++++\+Remove+non-unique+elements
L++++++\+Get+the+new+length
%5E=+++++\+Compare+with+the+previously+saved+length
#++++++\+Print+result|1277369|这是因为如果初始列表中只有一个非分明的整数，那么长度只会减少1。|1277370|在网上试试！|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/FTcode/Pushy|1|https://tio.run/##Kygtzqj8/9@npKzUJ85W@f///9GGOmY6xjomQGiuYxkLAA^0|0|4|0|0|2|T|0|0|0|0|0|0|6|1^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@$A|15|B|16|1|17]]|C|$]]|$1|D|3|E|5|F|7|18|8|@$A|19|B|1A|G|H]]|9|@]|C|$]]|$1|I|3|J|5|K|7|1B|8|@]|9|@]|C|$L|M]]|$1|N|3|O|5|F|7|1C|8|@]|9|@]|C|$]]|$1|P|3|Q|5|K|7|1D|8|@]|9|@]|C|$L|M]]|$1|R|3|S|5|F|7|1E|8|@]|9|@]|C|$]]|$1|T|3|U|5|F|7|1F|8|@]|9|@$A|1G|B|1H|1|1I]]|C|$]]]|V|$W|$5|X|Y|Z|C|$10|11]]|12|$5|X|Y|Z|C|$10|13]]]]

<h1><a href="https://github.com/FTcode/Pushy" rel="nofollow noreferrer">Pushy</a>, 8 bytes</h1>

<p>Simple implementation of checking whether <code>len(set(list)) == len(list)-1</code>:</p>

<pre><code>LtvuL^=#
</code></pre>

<p>Explanation:</p>

<pre><code>       \ Implicit: Put all input on stack
Ltv    \ Get the stack length - 1, save in auxiliary stack
u      \ Remove non-unique elements
L      \ Get the new length
^=     \ Compare with the previously saved length
#      \ Print result
</code></pre>

<p>This works as the length will only decrease by 1 if there was only exactly 1 non-distinct integer in the initial list.</p>

<p><a href="https://tio.run/##Kygtzqj8/9@npKzUJ85W@f///9GGOmY6xjomQGiuYxkLAA" rel="nofollow noreferrer" title="Pushy – Try It Online">Try it online!</a></p>


blocks|key|1277577|text|05AB1E，4字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1277578|{¥_O|code-block|syntax|javascript|1277579|在网上试试！|unstyled|1277580|输出1是真实的，任何其他非负整数都是假的.在05AB1E中，1是唯一真实的数字(感谢@Emigna的洞察力！)|style|CODE|1277581|解释|1277582|{+++++++Implicit+input.+Sort
+¥++++++Consecutive+differences
++_+++++Boolean+negate
+++O++++Sum.+Implicit+display|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/Adriandmen/05AB1E|1|https://tio.run/##MzBNTDJM/f@/@tDSeP///6MNdcx0jHVMgNBcxzIWAA^0|0|6|0|0|0|0|6|1|0|2|1|U|1|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@$A|13|B|14|1|15]]|C|$]]|$1|D|3|E|5|F|7|16|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|17|8|@]|9|@$A|18|B|19|1|1A]]|C|$]]|$1|L|3|M|5|K|7|1B|8|@$A|1C|B|1D|N|O]|$A|1E|B|1F|N|O]]|9|@]|C|$]]|$1|P|3|Q|5|6|7|1G|8|@]|9|@]|C|$]]|$1|R|3|S|5|F|7|1H|8|@]|9|@]|C|$G|H]]]|T|$U|$5|V|W|X|C|$Y|Z]]|10|$5|V|W|X|C|$Y|11]]]]

<h1><a href="https://github.com/Adriandmen/05AB1E" rel="nofollow noreferrer">05AB1E</a>, 4 bytes</h1>
<pre><code>{¥_O
</code></pre>
<p><a href="https://tio.run/##MzBNTDJM/f@/@tDSeP///6MNdcx0jHVMgNBcxzIWAA" rel="nofollow noreferrer" title="05AB1E – Try It Online">Try it online!</a></p>
<p>Outputs <code>1</code> as truthy, any other non-negative integer as falsy. In 05AB1E, <code>1</code> is the only truthy number (thanks @Emigna for the insight!).</p>
<h3>Explanation</h3>
<pre><code>{       Implicit input. Sort
 ¥      Consecutive differences
  _     Boolean negate
   O    Sum. Implicit display
</code></pre>


blocks|key|1277863|text|Ruby，32字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|1277864|->(s){s.uniq.length==s.length-1}|code-block|syntax|javascript|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|I|8|@]|9|@]|A|$E|F]]]|G|$]]

<h1>Ruby, 32 bytes</h1>

<pre><code>-&gt;(s){s.uniq.length==s.length-1}
</code></pre>


blocks|key|1278014|text|皮斯，6字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1278015|qtlQl{|code-block|syntax|javascript|1278016|验证所有测试用例。|1278017|l{+-获取唯一元素的数量。|unordered-list-item|style|CODE|1278018|tlQ+-获取输入列表的长度，递减。|1278019|q+-检查等式。|1278020|7字节|1278021|q1l.-Q{|1278022|验证所有测试用例|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/isaacg1/pyth|1|https://pyth.herokuapp.com/?code=qtlQl%257B&test_suite=1&test_suite_input=%255B1%252C1%255D%250A%255B1%252C2%252C1%255D%250A%255B1%252C6%252C3%252C4%252C4%252C7%252C9%255D%250A%255B0%255D%250A%255B1%252C1%252C1%255D%250A%255B1%252C1%252C1%252C2%255D%250A%255B1%252C1%252C2%252C2%255D%250A%255B2%252C1%252C2%252C1%252C2%255D%250A%255B1%252C2%252C3%252C4%252C5%255D&debug=0|2|https://pyth.herokuapp.com/?code=O&test_suite=1&test_suite_input=%255B1%252C1%255D%250A%255B1%252C2%252C1%255D%250A%255B1%252C6%252C3%252C4%252C4%252C7%252C9%255D%250A%255B0%255D%250A%255B1%252C1%252C1%255D%250A%255B1%252C1%252C1%252C2%255D%250A%255B1%252C1%252C2%252C2%255D%250A%255B2%252C1%252C2%252C1%252C2%255D%250A%255B1%252C2%252C3%252C4%252C5%255D&debug=0^0|0|2|0|0|0|0|9|1|0|0|2|0|0|3|0|0|1|0|0|0|0|8|2^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|D|3|E|5|F|7|1E|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|1F|8|@]|9|@$A|1G|B|1H|1|1I]]|C|$]]|$1|K|3|L|5|M|7|1J|8|@$A|1K|B|1L|N|O]]|9|@]|C|$]]|$1|P|3|Q|5|M|7|1M|8|@$A|1N|B|1O|N|O]]|9|@]|C|$]]|$1|R|3|S|5|M|7|1P|8|@$A|1Q|B|1R|N|O]]|9|@]|C|$]]|$1|T|3|U|5|6|7|1S|8|@]|9|@]|C|$]]|$1|V|3|W|5|F|7|1T|8|@]|9|@]|C|$G|H]]|$1|X|3|Y|5|6|7|1U|8|@]|9|@$A|1V|B|1W|1|1X]]|C|$]]]|Z|$10|$5|11|12|13|C|$14|15]]|16|$5|11|12|13|C|$14|17]]|18|$5|11|12|13|C|$14|19]]]]

<h1><a href="https://github.com/isaacg1/pyth" rel="nofollow noreferrer">Pyth</a>, 6 bytes</h1>
<pre><code>qtlQl{
</code></pre>
<p><strong><a href="https://pyth.herokuapp.com/?code=qtlQl%7B&amp;test_suite=1&amp;test_suite_input=%5B1%2C1%5D%0A%5B1%2C2%2C1%5D%0A%5B1%2C6%2C3%2C4%2C4%2C7%2C9%5D%0A%5B0%5D%0A%5B1%2C1%2C1%5D%0A%5B1%2C1%2C1%2C2%5D%0A%5B1%2C1%2C2%2C2%5D%0A%5B2%2C1%2C2%2C1%2C2%5D%0A%5B1%2C2%2C3%2C4%2C5%5D&amp;debug=0" rel="nofollow noreferrer">Verify all the test cases.</a></strong></p>
<ul>
<li><p><code>l{</code> - Gets the number of unique elements.</p>
</li>
<li><p><code>tlQ</code> - Gets the length of the input list, decremented.</p>
</li>
<li><p><code>q</code> - Checks equality.</p>
</li>
</ul>
<h1>7 bytes</h1>
<pre><code>q1l.-Q{
</code></pre>
<p><strong><a href="https://pyth.herokuapp.com/?code=O&amp;test_suite=1&amp;test_suite_input=%5B1%2C1%5D%0A%5B1%2C2%2C1%5D%0A%5B1%2C6%2C3%2C4%2C4%2C7%2C9%5D%0A%5B0%5D%0A%5B1%2C1%2C1%5D%0A%5B1%2C1%2C1%2C2%5D%0A%5B1%2C1%2C2%2C2%5D%0A%5B2%2C1%2C2%2C1%2C2%5D%0A%5B1%2C2%2C3%2C4%2C5%5D&amp;debug=0" rel="nofollow noreferrer">Verify all the test cases</a></strong></p>


blocks|key|1278123|text|C#+(.NET+Core)，35+%2B+18字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1278124|%2B18使用System.Linq。|unstyled|style|CODE|1278125|n=>n.Distinct().Count()==n.Length-1|code-block|syntax|javascript|1278126|在网上试试！|1278127|没有Linq的|1278128|67字节替代方案：|1278129|n=>new+System.Collections.Generic.HashSet<int>(n).Count==n.Length-1|1278130|entityMap|0|LINK|mutability|MUTABLE|url|https://www.microsoft.com/net/core/platform|1|https://tio.run/##LY6xDoJAEERr@IotIYFLsEVoNFaamFhYEIrzPHET3Iu3i8YQvv2EhGammXkzhnPjvA0DI3Vw@bHYlzoivcvY9JoZzt51Xr9gjCMWLWjg4/AOJ42UsPi51bSgfcfpEolWwmEgs0WSps3g5lxfwwOqQFVNao8sSEaSVO3cQLNXFamjpU6eeRHKeEXsHLHrrbp6FDs/sskjIfud10YoMthkixZTmpbxNIU/|2|https://tio.run/##Pc6xCsJAEEXR2nzFlAnEhdhq0ghqoSCksBCLdR2Tgc0s7IyKhHx7jCD25z6ek7kLEUfnrQgcY2ii7aBPZqJWycEz0A0OljgVjcTN@QI2NpJ9yax@i2JnNg92K2I9X3K4huAruEM5clkxvuBn1sF7dEqBxWyRMZIzOyttjQrftko5m9CDtSzZ7JEbbefFuEz@PUvwaE6RFPfEmN7TaX6600ORwyKHYsiyZTIM4wc^0|0|E|0|0|5|B|0|0|0|6|1|0|0|0|0|0|6|2^^$0|@$1|2|3|4|5|6|7|17|8|@]|9|@$A|18|B|19|1|1A]]|C|$]]|$1|D|3|E|5|F|7|1B|8|@$A|1C|B|1D|G|H]]|9|@]|C|$]]|$1|I|3|J|5|K|7|1E|8|@]|9|@]|C|$L|M]]|$1|N|3|O|5|F|7|1F|8|@]|9|@$A|1G|B|1H|1|1I]]|C|$]]|$1|P|3|Q|5|F|7|1J|8|@]|9|@]|C|$]]|$1|R|3|S|5|6|7|1K|8|@]|9|@]|C|$]]|$1|T|3|U|5|K|7|1L|8|@]|9|@]|C|$L|M]]|$1|V|3|O|5|F|7|1M|8|@]|9|@$A|1N|B|1O|1|1P]]|C|$]]]|W|$X|$5|Y|Z|10|C|$11|12]]|13|$5|Y|Z|10|C|$11|14]]|15|$5|Y|Z|10|C|$11|16]]]]

<h1><a href="https://www.microsoft.com/net/core/platform" rel="nofollow noreferrer">C# (.NET Core)</a>, 35 + 18 bytes</h1>

<p>+18 for using <code>System.Linq</code>.</p>



<pre class="lang-cs prettyprint-override"><code>n=&gt;n.Distinct().Count()==n.Length-1
</code></pre>

<p><a href="https://tio.run/##LY6xDoJAEERr@IotIYFLsEVoNFaamFhYEIrzPHET3Iu3i8YQvv2EhGammXkzhnPjvA0DI3Vw@bHYlzoivcvY9JoZzt51Xr9gjCMWLWjg4/AOJ42UsPi51bSgfcfpEolWwmEgs0WSps3g5lxfwwOqQFVNao8sSEaSVO3cQLNXFamjpU6eeRHKeEXsHLHrrbp6FDs/sskjIfud10YoMthkixZTmpbxNIU/" rel="nofollow noreferrer" title="C# (.NET Core) – Try It Online">Try it online!</a></p>

<p><strong>67 byte alternative without Linq:</strong></p>



<pre class="lang-cs prettyprint-override"><code>n=&gt;new System.Collections.Generic.HashSet&lt;int&gt;(n).Count==n.Length-1
</code></pre>

<p><a href="https://tio.run/##Pc6xCsJAEEXR2nzFlAnEhdhq0ghqoSCksBCLdR2Tgc0s7IyKhHx7jCD25z6ek7kLEUfnrQgcY2ii7aBPZqJWycEz0A0OljgVjcTN@QI2NpJ9yax@i2JnNg92K2I9X3K4huAruEM5clkxvuBn1sF7dEqBxWyRMZIzOyttjQrftko5m9CDtSzZ7JEbbefFuEz@PUvwaE6RFPfEmN7TaX6600ORwyKHYsiyZTIM4wc" rel="nofollow noreferrer" title="C# (.NET Core) – Try It Online">Try it online!</a></p>


blocks|key|140688|text|Excel，42字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|140689|丹麦语版本|140690|=TÆLV(A:A)=SUM(--(FREKVENS(A:A,A:A)>0))%2B1|code-block|syntax|javascript|140691|在列A中的单独单元格中假设列表中的每个整数。|unstyled|offset|length|style|CODE|140692|140693|如果允许使用不一致的falsey值，则可以保存3个字节：|140694|=TÆLV(A:A)%2BSUM(-(FREKVENS(A:A,A:A)>0))|140695|英语版本(44个字节)|140696|=COUNTA(A:A)=SUM(--(FREQUENCY(A:A,A:A)>0))%2B1|entityMap^0|0|0|0|2|1|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|10|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|11|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|K|7|12|8|@$L|13|M|14|N|O]]|9|@]|A|$]]|$1|P|3|-4|5|K|7|15|8|@]|9|@]|A|$]]|$1|Q|3|R|5|K|7|16|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|17|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|18|8|@]|9|@]|A|$]]|$1|W|3|X|5|F|7|19|8|@]|9|@]|A|$G|H]]]|Y|$]]

<h2>Excel, 42 bytes</h2>
<p><strong>Danish language version</strong></p>
<pre><code>=TÆLV(A:A)=SUM(--(FREKVENS(A:A,A:A)&gt;0))+1
</code></pre>
<p>Assumes each integer from the list in separate cell in column <code>A</code>.<br />
If we were allowed for inconsistent <em>falsey</em> values, we could save 3 bytes:</p>
<pre><code>=TÆLV(A:A)+SUM(-(FREKVENS(A:A,A:A)&gt;0))
</code></pre>
<p><strong>English language version (44 bytes)</strong></p>
<pre><code>=COUNTA(A:A)=SUM(--(FREQUENCY(A:A,A:A)&gt;0))+1
</code></pre>


blocks|key|140279|text|05AB1E，5字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|140280|gIÙg-|code-block|syntax|javascript|140281|在网上试试！|unstyled|140282|g+++++#+Get+number+of+elements+in+input
+IÙg++#+Get+number+of+unique+elements+in+input
++++-+#+Subtract|140283|在05AB1E1中，唯一的真实值，所以对于一个真实的结果，必须有一个重复的元素被唯一删除。|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/Adriandmen/05AB1E|1|https://tio.run/##MzBNTDJM/f8/3fPwzHTd//@jDXWMdIx1THRMYgE^0|0|6|0|0|0|0|6|1|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|13|8|@]|9|@$A|14|B|15|1|16]]|C|$]]|$1|L|3|M|5|F|7|17|8|@]|9|@]|C|$G|H]]|$1|N|3|O|5|K|7|18|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]|W|$5|R|S|T|C|$U|X]]]]

<h1><a href="https://github.com/Adriandmen/05AB1E" rel="nofollow noreferrer">05AB1E</a>, 5 bytes</h1>

<pre><code>gIÙg-
</code></pre>

<p><a href="https://tio.run/##MzBNTDJM/f8/3fPwzHTd//@jDXWMdIx1THRMYgE" rel="nofollow noreferrer" title="05AB1E – Try It Online">Try it online!</a></p>

<pre><code>g     # Get number of elements in input
 IÙg  # Get number of unique elements in input
    - # Subtract
</code></pre>

<p>In 05AB1E 1 is the only truthy  value, so for a truthy result there must be exactly 1 duplicate element removed by the uniquify.</p>


blocks|key|1277633|text|哈斯克尔，37字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1277634|f+x=sum[1%7Ca<-x,b<-x,a==b]==2%2Blength+x|code-block|syntax|javascript|1277635|在网上试试！|unstyled|entityMap|0|LINK|mutability|MUTABLE|url|https://www.haskell.org/|1|https://tio.run/##y0gszk7Nyfn/P02hwra4NDfasCbRRrdCJwlEJNraJsXa2hpp56TmpZdkKFT8z03MzFOwVUjJ51IAgoKizLwSBRWFNIVoQx3DWEwxI6yiZjrGOiZAaK5jiSFrgEU9drNB0AiruBEWcSOwOHYdRmD3mMZy/QcA^0|0|4|0|0|0|0|6|1^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]]]

<h1><a href="https://www.haskell.org/" rel="nofollow noreferrer">Haskell</a>, 37 bytes</h1>



<pre class="lang-hs prettyprint-override"><code>f x=sum[1|a&lt;-x,b&lt;-x,a==b]==2+length x
</code></pre>

<p><a href="https://tio.run/##y0gszk7Nyfn/P02hwra4NDfasCbRRrdCJwlEJNraJsXa2hpp56TmpZdkKFT8z03MzFOwVUjJ51IAgoKizLwSBRWFNIVoQx3DWEwxI6yiZjrGOiZAaK5jiSFrgEU9drNB0AiruBEWcSOwOHYdRmD3mMZy/QcA" rel="nofollow noreferrer" title="Haskell – Try It Online">Try it online!</a></p>


blocks|key|1277719|text|八度+/+MATLAB+(有统计软件包/工具箱)，21字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1277720|@(x)nnz(~pdist(x))==1|code-block|syntax|javascript|1277721|匿名函数。输入是列向量。输出是true+(显示为1)或false+(显示为0)。|unstyled|style|CODE|1277722|在网上试试！|1277723|解释|1277724|pdist(x)计算来自x的所有行对之间欧氏距离的向量。它只考虑每对一次(两行的顺序无关紧要)，而不考虑由同一行两次形成的对。|1277725|在我们的例子中，x是一个列向量，所以两行之间的欧几里德距离只是两个数字之间的绝对差。|1277726|~是逻辑(布尔)否定，nnz是非零数，==1是1。因此，结果是true当且仅当只有一对给出零距离。|entityMap|0|LINK|mutability|MUTABLE|url|https://www.gnu.org/software/octave/|1|https://tio.run/##y08uSSxL/Z9mq6en999Bo0IzL69Ko64gJbO4BMjRtLU1/J@mEW1orWAYq8kFYRkhc8ysFYytFUzAyNxawRIiYQCXR9EJQUbIfCM43wjGR1FiBDPfNFbzPwA^0|0|2|0|0|0|F|4|O|1|R|5|11|1|0|0|6|1|0|0|0|8|C|1|0|8|1|0|0|1|B|3|J|3|N|1|V|4^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@$A|17|B|18|1|19]]|C|$]]|$1|D|3|E|5|F|7|1A|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|1B|8|@$A|1C|B|1D|L|M]|$A|1E|B|1F|L|M]|$A|1G|B|1H|L|M]|$A|1I|B|1J|L|M]]|9|@]|C|$]]|$1|N|3|O|5|K|7|1K|8|@]|9|@$A|1L|B|1M|1|1N]]|C|$]]|$1|P|3|Q|5|6|7|1O|8|@]|9|@]|C|$]]|$1|R|3|S|5|K|7|1P|8|@$A|1Q|B|1R|L|M]|$A|1S|B|1T|L|M]]|9|@]|C|$]]|$1|T|3|U|5|K|7|1U|8|@$A|1V|B|1W|L|M]]|9|@]|C|$]]|$1|V|3|W|5|K|7|1X|8|@$A|1Y|B|1Z|L|M]|$A|20|B|21|L|M]|$A|22|B|23|L|M]|$A|24|B|25|L|M]|$A|26|B|27|L|M]]|9|@]|C|$]]]|X|$Y|$5|Z|10|11|C|$12|13]]|14|$5|Z|10|11|C|$12|15]]]]

<h1><a href="https://www.gnu.org/software/octave/" rel="nofollow noreferrer">Octave</a> / MATLAB (with Statistics package / toolbox), 21 bytes</h1>

<pre class="lang-matlab prettyprint-override"><code>@(x)nnz(~pdist(x))==1
</code></pre>
<p>Anonymous function. Input is a column vector. Output is <code>true</code> (displayed as <code>1</code>) or <code>false</code> (displayed as<code>0</code>).</p>
<p><a href="https://tio.run/##y08uSSxL/Z9mq6en999Bo0IzL69Ko64gJbO4BMjRtLU1/J@mEW1orWAYq8kFYRkhc8ysFYytFUzAyNxawRIiYQCXR9EJQUbIfCM43wjGR1FiBDPfNFbzPwA" rel="nofollow noreferrer" title="Octave – Try It Online"><strong>Try it online!</strong></a></p>
<h3>Explanation</h3>
<p><code>pdist(x)</code> computes a vector of Euclidean distances between all pairs of rows from <code>x</code>. It considers each pair only once (order of the two rows doesn't matter), and doesn't consider pairs formed by the same row twice.</p>
<p>In our case <code>x</code> is a column vector, so Euclidean distance between two rows is just absolute difference between the two numbers.</p>
<p><code>~</code> is logical (Boolean) negation, <code>nnz</code> is number of nonzeros, and <code>==1</code> compares to <code>1</code>. So the result is <code>true</code> if and only if there is only one pair that gives zero distance.</p>


blocks|key|1277020|text|果冻，10字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1277021|ċ@€`QṢ⁼1,2|code-block|syntax|javascript|1277022|在网上试试！|unstyled|1277023|一种较长但不同的方法|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/DennisMitchell/jelly|1|https://tio.run/##y0rNyan8//9It8OjpjUJgQ93LnrUuMdQx@j///@GOmY6xjomQGipYw4A^0|0|2|0|0|0|0|6|1|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|11|8|@]|9|@$A|12|B|13|1|14]]|C|$]]|$1|L|3|M|5|K|7|15|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]]]

<h1><a href="https://github.com/DennisMitchell/jelly" rel="nofollow noreferrer">Jelly</a>, 10 bytes</h1>

<pre><code>ċ@€`QṢ⁼1,2
</code></pre>

<p><a href="https://tio.run/##y0rNyan8//9It8OjpjUJgQ93LnrUuMdQx@j///@GOmY6xjomQGipYw4A" rel="nofollow noreferrer" title="Jelly – Try It Online">Try it online!</a></p>

<p>a longer but different approach</p>


blocks|key|139913|text|Japt，7字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|139914|â+Ê¶UÊÉ|code-block|syntax|javascript|139915|试试看|unstyled|offset|length|139916|解释|139917|删除重复项(â)，获取长度(Ê)，并将等式(¶)与输入(U)减去1+(É)的长度(Ê)进行比较。|style|CODE|entityMap|0|LINK|mutability|MUTABLE|url|https://ethproductions.github.io/japt/?v=1.4.5&code=4iDKtlXKyQ==&input=WzEsNiwzLDQsNCw3LDld^0|0|0|0|3|0|0|0|6|1|E|1|M|1|S|1|Z|1|15|1^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|I|7|10|8|@]|9|@$J|11|K|12|1|13]]|A|$]]|$1|L|3|M|5|6|7|14|8|@]|9|@]|A|$]]|$1|N|3|O|5|I|7|15|8|@$J|16|K|17|P|Q]|$J|18|K|19|P|Q]|$J|1A|K|1B|P|Q]|$J|1C|K|1D|P|Q]|$J|1E|K|1F|P|Q]|$J|1G|K|1H|P|Q]]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]]]

<h1>Japt, 7 bytes</h1>
<pre><code>â Ê¶UÊÉ
</code></pre>
<p><a href="https://ethproductions.github.io/japt/?v=1.4.5&amp;code=4iDKtlXKyQ==&amp;input=WzEsNiwzLDQsNCw3LDld" rel="nofollow noreferrer">Try it</a></p>
<hr />
<h2>Explanation</h2>
<p>Remove duplicates (<code>â</code>), get length (<code>Ê</code>) and compare equality (<code>¶</code>) with the length (<code>Ê</code>) of the input (<code>U</code>) minus 1 (<code>É</code>).</p>


blocks|key|140116|text|哈斯克尔，37字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|140117|f+x=sum[1%7C0<-(-)<A3gt;x<*>x]==2%2Blength+x|code-block|syntax|javascript|140118|在网上试试！|unstyled|entityMap|0|LINK|mutability|MUTABLE|url|https://www.haskell.org/|1|https://tio.run/##y0gszk7Nyfn/P02hwra4NDfasMbARldDV9NGxa7CRsuuItbW1kg7JzUvvSRDoeJ/bmJmnoKtQkFRZl6JgopCmkK0oY6hjrGOSex/AA^0|0|4|0|0|0|0|6|1^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]]]

<h1><a href="https://www.haskell.org/" rel="nofollow noreferrer">Haskell</a>, 37 bytes</h1>



<pre class="lang-hs prettyprint-override"><code>f x=sum[1|0&lt;-(-)&lt;$&gt;x&lt;*&gt;x]==2+length x
</code></pre>

<p><a href="https://tio.run/##y0gszk7Nyfn/P02hwra4NDfasMbARldDV9NGxa7CRsuuItbW1kg7JzUvvSRDoeJ/bmJmnoKtQkFRZl6JgopCmkK0oY6hjrGOSex/AA" rel="nofollow noreferrer" title="Haskell – Try It Online">Try it online!</a></p>


blocks|key|1277842|text|Bash+%2B+coreutils，36字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1277843|sort%7Cuniq+-dc%7Cgrep+-Pqz+'%5E+*2+.*\n输出是通过退出代码输出的，其中0表示成功(真)，1表示失败(falsy)。在网上试试！|code-block|syntax|javascript|1277844|输出是通过退出代码输出的，其中0表示成功(真)，1表示失败(falsy)。|unstyled|1277845|在网上试试！|entityMap|0|LINK|mutability|MUTABLE|url|https://www.gnu.org/software/bash/|1|https://tio.run/##S0oszvj/vzi/qKSmNC@zUEE3JbkmvSi1QEE3oLBKQT1OQctIQU8rJk9F/f9/Qy4zLmMuEyA057IEAA^0|0|4|0|0|0|0|0|6|1^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|11|8|@]|9|@]|C|$]]|$1|L|3|M|5|K|7|12|8|@]|9|@$A|13|B|14|1|15]]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]]]

<h1><a href="https://www.gnu.org/software/bash/" rel="nofollow noreferrer">Bash</a> + coreutils, 36 bytes</h1>



<pre class="lang-bash prettyprint-override"><code>sort|uniq -dc|grep -Pqz '^ *2 .*\n$'
</code></pre>

<p>Output is via exit code, where <strong>0</strong> is success (truthy) and <strong>1</strong> is failure (falsy).</p>

<p><a href="https://tio.run/##S0oszvj/vzi/qKSmNC@zUEE3JbkmvSi1QEE3oLBKQT1OQctIQU8rJk9F/f9/Qy4zLmMuEyA057IEAA" rel="nofollow noreferrer" title="Bash – Try It Online">Try it online!</a></p>


blocks|key|1278246|text|克洛尔，31字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1278247|#(=(count(set+%25))(-(count+%25)1))|code-block|syntax|javascript|1278248|在网上试试！|unstyled|1278249|是否与LyricLy的回答相同？|entityMap|0|LINK|mutability|MUTABLE|url|https://clojure.org/|1|https://tio.run/##S87JzyotSv2vkZtYUKagkZyfW6BQUJSZV5KT919ZwxYoUJpXolGcWqKgqqmpkZKaDBEB8TT/a3JFRxsqGMZyKQApIxjDTMFYwQQIzRUsQQIGEFG4OhA0gjGNIEwjMBMubgQ2wTQ2VvM/AA|2|https://codegolf.stackexchange.com/a/145032/75204^0|0|3|0|0|0|0|6|1|0|3|A|2^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|13|8|@]|9|@$A|14|B|15|1|16]]|C|$]]|$1|L|3|M|5|K|7|17|8|@]|9|@$A|18|B|19|1|1A]]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]|W|$5|P|Q|R|C|$S|X]]]]

<h1><a href="https://clojure.org/" rel="nofollow noreferrer">Clojure</a>, 31 bytes</h1>



<pre class="lang-clj prettyprint-override"><code>#(=(count(set %))(-(count %)1))
</code></pre>

<p><a href="https://tio.run/##S87JzyotSv2vkZtYUKagkZyfW6BQUJSZV5KT919ZwxYoUJpXolGcWqKgqqmpkZKaDBEB8TT/a3JFRxsqGMZyKQApIxjDTMFYwQQIzRUsQQIGEFG4OhA0gjGNIEwjMBMubgQ2wTQ2VvM/AA" rel="nofollow noreferrer" title="Clojure – Try It Online">Try it online!</a></p>

<p>Does the same as <a href="https://codegolf.stackexchange.com/a/145032/75204">LyricLy's answer</a></p>


blocks|key|1278453|text|杰夫特，7字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1278454|ÊÉ¶Uâ+Ê
++++++Ê+//+Return+whether+the+number+of
+++Uâ+++//+unique+items+in+the+input
++¶+++++//+is+equal+to
ÊÉ++++++//+the+input's+length+minus+one.|code-block|syntax|javascript|1278455|在网上试试！|unstyled|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/ETHproductions/japt|1|https://tio.run/##y0osKPn//3DX4c5D20IPL1I43PX/f7ShjpmOsY4JEFrGAgA^0|0|3|0|0|0|0|6|1^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]]]

<h1><a href="https://github.com/ETHproductions/japt" rel="nofollow noreferrer">Japt</a>, 7 bytes</h1>



<pre class="lang-js prettyprint-override"><code>ÊÉ¶Uâ Ê
      Ê // Return whether the number of
   Uâ   // unique items in the input
  ¶     // is equal to
ÊÉ      // the input's length minus one.
</code></pre>

<p><a href="https://tio.run/##y0osKPn//3DX4c5D20IPL1I43PX/f7ShjpmOsY4JEFrGAgA" rel="nofollow noreferrer" title="Japt – Try It Online">Try it online!</a></p>


blocks|key|141012|text|布氏对数，7字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|141013|dl.&l-₁|code-block|syntax|javascript|141014|在网上试试！|unstyled|141015|Truthy/falsy输入是通过谓词的成功/失败来实现的，就像这个谓词作为整个程序在单个输入上运行一样，如果它成功，它将打印true.，如果它失败，它将打印false.。TIO上的头在那里，所以您可以同时运行所有的情况。|style|CODE|141016|dl+++++++++The+length+of+the+input+with+duplicates+removed
++.++++++++is+the+output+variable,
+++&+++++++and
++++l-₁++++so+is+the+length+of+the+input+minus+1.|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/JCumin/Brachylog|1|https://tio.run/##SypKTM6ozMlPN/pf/ahtw6Ompkcdy5VKikpTlfRqQMy0xJziVKXa04vK/6fk6Knl6D5qavz/PzraUMcwVgdIGkFpMx1jHRMgNNexBPINwGIwNSBoBGUZgVlGYBZM1Ais1zQ2FgA^0|0|4|0|0|0|0|6|1|0|1R|5|27|6|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|15|8|@]|9|@$A|16|B|17|1|18]]|C|$]]|$1|L|3|M|5|K|7|19|8|@$A|1A|B|1B|N|O]|$A|1C|B|1D|N|O]]|9|@]|C|$]]|$1|P|3|Q|5|F|7|1E|8|@]|9|@]|C|$G|H]]]|R|$S|$5|T|U|V|C|$W|X]]|Y|$5|T|U|V|C|$W|Z]]]]

<h1><a href="https://github.com/JCumin/Brachylog" rel="nofollow noreferrer">Brachylog</a>, 7 bytes</h1>

<pre><code>dl.&amp;l-₁
</code></pre>

<p><a href="https://tio.run/##SypKTM6ozMlPN/pf/ahtw6Ompkcdy5VKikpTlfRqQMy0xJziVKXa04vK/6fk6Knl6D5qavz/PzraUMcwVgdIGkFpMx1jHRMgNNexBPINwGIwNSBoBGUZgVlGYBZM1Ais1zQ2FgA" rel="nofollow noreferrer" title="Brachylog – Try It Online">Try it online!</a></p>

<p>Truthy/falsy input is achieved through predicate success/failure, as if this predicate is run as the entire program on a single input, it will print <code>true.</code> if it succeeds and <code>false.</code> if it fails. The header on TIO is there so you can run all of the cases at once.</p>

<pre><code>dl         The length of the input with duplicates removed
  .        is the output variable,
   &amp;       and
    l-₁    so is the length of the input minus 1.
</code></pre>


blocks|key|139939|text|Mathematica，26字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|139940|(l=Length)@Union@#%2B1==l@#&|code-block|syntax|javascript|139941|在网上试试！|unstyled|offset|length|entityMap|0|LINK|mutability|MUTABLE|url|https://tio.run/##y00syUjNTSzJTE78n277XyPH1ic1L70kQ9MhNC8zP89BWdvQ1jbHQVntf0BRZl6JgkN6dLWhjmFtLBcy3whDxEzHWMcECM11LFFkDNDUYZoFgkYYYkZoYkZgMUyVRmB7TWtj//8HAA^0|0|0|0|6|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|I|7|U|8|@]|9|@$J|V|K|W|1|X]]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

<h1>Mathematica, 26 bytes</h1>
<pre><code>(l=Length)@Union@#+1==l@#&amp;
</code></pre>
<p><a href="https://tio.run/##y00syUjNTSzJTE78n277XyPH1ic1L70kQ9MhNC8zP89BWdvQ1jbHQVntf0BRZl6JgkN6dLWhjmFtLBcy3whDxEzHWMcECM11LFFkDNDUYZoFgkYYYkZoYkZgMUyVRmB7TWtj//8HAA" rel="nofollow noreferrer" title="Wolfram Language (Mathematica) – Try It Online">Try it online!</a></p>


blocks|key|139963|text|凸性，7字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|139964|_Å,)\,=|code-block|syntax|javascript|139965|在网上试试！|unstyled|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/GamrCorps/Convex|1|https://tio.run/##S87PK0ut@P8//nCrjmaMju3///@jDRXMFIwVTIDQXMEyFgA^0|0|2|0|0|0|0|6|1^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]]]

<h1><a href="https://github.com/GamrCorps/Convex" rel="nofollow noreferrer">Convex</a>, 7 bytes</h1>

<pre><code>_Å,)\,=
</code></pre>

<p><a href="https://tio.run/##S87PK0ut@P8//nCrjmaMju3///@jDRXMFIwVTIDQXMEyFgA" rel="nofollow noreferrer" title="Convex – Try It Online">Try it online!</a></p>


blocks|key|140509|text|批处理，109个字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|140510|@set/ap=1,s=0
@for+%25%25x+in+(%25*)do+@(for+%25%25y+in+(%25*)do+@set/a"s%2B=!(%25%25x-%25%25y)")&set/ap*=s,s=0
@if+%25p%25==4+echo+1|code-block|syntax|javascript|140511|@DJMcMayhem的回答。|unstyled|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|I|7|M|8|@]|9|@]|A|$]]]|J|$]]

<h2>Batch, 109 bytes</h2>

<pre><code>@set/ap=1,s=0
@for %%x in (%*)do @(for %%y in (%*)do @set/a"s+=!(%%x-%%y)")&amp;set/ap*=s,s=0
@if %p%==4 echo 1
</code></pre>

<p>Port of @DJMcMayhem's answer.</p>


blocks|key|1278291|text|Perl+6，12字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1278292|{.Set%2B1==$_}|code-block|syntax|javascript|1278293|在网上试试！|unstyled|1278294|转换为Set，测试元素的数量是否小于一个。|entityMap|0|LINK|mutability|MUTABLE|url|http://perl6.org/|1|https://tio.run/##K0gtyjH7n1upoJamYPu/Wi84tUTb0NZWJb72v7VCcWKlglJ1mgKQZwUklBTS8osUbAwVDO10QJQRjGGmYKxgAoTmCpYgAQOIKFQdUJUCGNtZ/wcA^0|0|6|0|0|0|0|6|1|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|11|8|@]|9|@$A|12|B|13|1|14]]|C|$]]|$1|L|3|M|5|K|7|15|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]]]

<h1><a href="http://perl6.org/" rel="nofollow noreferrer">Perl 6</a>, 12 bytes</h1>

<pre><code>{.Set+1==$_}
</code></pre>

<p><a href="https://tio.run/##K0gtyjH7n1upoJamYPu/Wi84tUTb0NZWJb72v7VCcWKlglJ1mgKQZwUklBTS8osUbAwVDO10QJQRjGGmYKxgAoTmCpYgAQOIKFQdUJUCGNtZ/wcA" rel="nofollow noreferrer" title="Perl 6 – Try It Online">Try it online!</a></p>

<p>Convert to Set, test if the number of elements is less by one.</p>


blocks|key|140855|text|R，40字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|140856|sum(outer(x<-scan(),x,"=="))==2%2Bsum(x%7C1)|code-block|syntax|javascript|140857|在网上试试！|unstyled|140858|方法不同于另一个R解决方案+-而不是像高尔夫一样.|style|CODE|entityMap|0|LINK|mutability|MUTABLE|url|https://www.r-project.org/|1|https://tio.run/##K/r/v7g0VyO/tCS1SKPCRrc4OTFPQ1OnQkfJ1lZJU9PW1kgbJF9RY6j531DBTMFYwQQIzRUs/wMA|2|https://codegolf.stackexchange.com/a/145056/80010^0|0|1|0|0|0|0|6|1|0|8|1|5|8|2^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|15|8|@]|9|@$A|16|B|17|1|18]]|C|$]]|$1|L|3|M|5|K|7|19|8|@$A|1A|B|1B|N|O]]|9|@$A|1C|B|1D|1|1E]]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]|W|$5|R|S|T|C|$U|X]]|Y|$5|R|S|T|C|$U|Z]]]]

<h1><a href="https://www.r-project.org/" rel="nofollow noreferrer">R</a>, 40 bytes</h1>



<pre class="lang-r prettyprint-override"><code>sum(outer(x&lt;-scan(),x,"=="))==2+sum(x|1)
</code></pre>

<p><a href="https://tio.run/##K/r/v7g0VyO/tCS1SKPCRrc4OTFPQ1OnQkfJ1lZJU9PW1kgbJF9RY6j531DBTMFYwQQIzRUs/wMA" rel="nofollow noreferrer" title="R – Try It Online">Try it online!</a></p>

<p>Approach is different from <a href="https://codegolf.stackexchange.com/a/145056/80010">the other <code>R</code> solution</a> - and not as golfy...</p>


blocks|key|140896|text|12-基本，31字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|140897|FUNC+S(L)?LEN(L%7CL)==LEN(L)-1END|code-block|syntax|javascript|140898|%7C+(union)运算符返回一个数组，其中包含两个输入数组中的元素。作为一个副作用，它删除重复。|unstyled|offset|length|style|CODE|entityMap^0|0|0|0|1^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|I|7|Q|8|@$J|R|K|S|L|M]]|9|@]|A|$]]]|N|$]]

<h1>12-basic, 31 bytes</h1>
<pre><code>FUNC S(L)?LEN(L|L)==LEN(L)-1END
</code></pre>
<p>The <code>|</code> (union) operator returns an array containing elements that are in both of the input arrays. As a side effect, it removes duplicates.</p>


blocks|key|141067|text|帕里/GP，16字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|141068|a->#a==#Set(a)%2B1|code-block|syntax|javascript|141069|在网上试试！|unstyled|entityMap|0|LINK|mutability|MUTABLE|url|http://pari.math.u-bordeaux.fr/|1|https://tio.run/##K0gsytRNL/ifpmD7P1HXTjnR1lY5OLVEI1FT2/B/YkFBTqVGooKunUJBUWYeUFRBCcRRUkgDKtDUUYiONtQxjAXShjpGMIaZjrGOCRCa61iCBAwgonB1IGgEYxpBmEZgJlzcCGyCaWys5n8A^0|0|5|0|0|0|0|6|1^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]]]

<h1><a href="http://pari.math.u-bordeaux.fr/" rel="nofollow noreferrer">Pari/GP</a>, 16 bytes</h1>

<pre><code>a-&gt;#a==#Set(a)+1
</code></pre>

<p><a href="https://tio.run/##K0gsytRNL/ifpmD7P1HXTjnR1lY5OLVEI1FT2/B/YkFBTqVGooKunUJBUWYeUFRBCcRRUkgDKtDUUYiONtQxjAXShjpGMIaZjrGOCRCa61iCBAwgonB1IGgEYxpBmEZgJlzcCGyCaWys5n8A" rel="nofollow noreferrer" title="Pari/GP – Try It Online">Try it online!</a></p>


blocks|key|141124|text|R，38字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|141125|不太像另一个R答案，而是一种不同的方法。|unstyled|141126|length(a<-scan())-length(unique(a))==1|code-block|syntax|javascript|141127|在网上试试！|entityMap|0|LINK|mutability|MUTABLE|url|https://www.r-project.org/|1|https://tio.run/##K/r/Pyc1L70kQyPRRrc4OTFPQ1NTFypSmpdZWJqqkaipaWtr@N9QwUjBWMFEwfA/AA^0|0|1|0|0|0|0|0|6|1^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$]]|$1|G|3|H|5|I|7|11|8|@]|9|@]|C|$J|K]]|$1|L|3|M|5|F|7|12|8|@]|9|@$A|13|B|14|1|15]]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]]]

<h1><a href="https://www.r-project.org/" rel="nofollow noreferrer">R</a>, 38 bytes</h1>

<p>Not quite as golfed as another R answer, but a different approach.</p>



<pre class="lang-r prettyprint-override"><code>length(a&lt;-scan())-length(unique(a))==1
</code></pre>

<p><a href="https://tio.run/##K/r/Pyc1L70kQyPRRrc4OTFPQ1NTFypSmpdZWJqqkaipaWtr@N9QwUjBWMFEwfA/AA" rel="nofollow noreferrer" title="R – Try It Online">Try it online!</a></p>


blocks|key|1278618|text|F#，49字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|1278619|let+s+c=Seq.distinct+c%7C>Seq.length=Seq.length+c-1|code-block|syntax|javascript|1278620|在网上试试！|unstyled|offset|length|1278621|Seq.distinct创建集合中所有唯一元素的序列。如果不同元素的数量比原始集合少一个，那么就会有灵魂伴侣。|style|CODE|entityMap|0|LINK|mutability|MUTABLE|url|https://tio.run/##TY9NC8IwDIbv/RVBEBScbPULmSt48C543DzM2s1C7WYXBcH/Pluds00P79Mkb5qiCXhlRNsqgdAATw7iNj3LBqXmCPzFHCuhS7wkfwk8iNp0s9NonvtKamRH4gyuudSQm/IBCYGUgD1pFEfHn6KeXsazeG5jFa@7t7DP@T0uqEe0J/ohP0s/ngvL9r4YuB9f8xpGxV0Dr5QSHGWlIWAeTdzePY37RonCfDtHfrERzV3h2HnUxq5eaBgMtxkGLMPhaeCP6UoJgbB9Aw^0|0|0|0|6|0|0|0|C^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|I|7|Y|8|@]|9|@$J|Z|K|10|1|11]]|A|$]]|$1|L|3|M|5|I|7|12|8|@$J|13|K|14|N|O]]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

<h2>F#, 49 bytes</h2>
<pre><code>let s c=Seq.distinct c|&gt;Seq.length=Seq.length c-1
</code></pre>
<p><a href="https://tio.run/##TY9NC8IwDIbv/RVBEBScbPULmSt48C543DzM2s1C7WYXBcH/Pluds00P79Mkb5qiCXhlRNsqgdAATw7iNj3LBqXmCPzFHCuhS7wkfwk8iNp0s9NonvtKamRH4gyuudSQm/IBCYGUgD1pFEfHn6KeXsazeG5jFa@7t7DP@T0uqEe0J/ohP0s/ngvL9r4YuB9f8xpGxV0Dr5QSHGWlIWAeTdzePY37RonCfDtHfrERzV3h2HnUxq5eaBgMtxkGLMPhaeCP6UoJgbB9Aw" rel="nofollow noreferrer">Try it online!</a></p>
<p><code>Seq.distinct</code> creates a sequence of all the unique elements in the collection. If the number of distinct elements is one less than the original collection, there are soulmates.</p>


blocks|key|141232|text|Javascript,96字节|type|header-two|depth|inlineStyleRanges|entityRanges|data|141233|for(i=0;i<a.length;i%2B%2B)for(j=0;j<a.length;j%2B%2B)(a[i]==a[j]&&+i!=j)?count%2B%2B:0+console.log(count==2)|code-block|syntax|javascript|141234|以及更好的可读性格式|unstyled|141235|for(i=0;i<a.length;i%2B%2B){
++for(j=0;j<a.length;j%2B%2B){
+++(a[i]==a[j]&&+i!=j)?count%2B%2B:0
++}
}
+console.log(count==2)|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|I|7|O|8|@]|9|@]|A|$]]|$1|J|3|K|5|D|7|P|8|@]|9|@]|A|$E|F]]]|L|$]]

<h1>Javascript,96 bytes</h1>
<pre><code>for(i=0;i&lt;a.length;i++)for(j=0;j&lt;a.length;j++)(a[i]==a[j]&amp;&amp; i!=j)?count++:0 console.log(count==2)
</code></pre>
<p>And a better readable format</p>
<pre><code>for(i=0;i&lt;a.length;i++){
  for(j=0;j&lt;a.length;j++){
   (a[i]==a[j]&amp;&amp; i!=j)?count++:0
  }
}
 console.log(count==2)
</code></pre>


blocks|key|141285|text|GolfScript，7字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|141286|.,\.&,-|code-block|syntax|javascript|141287|在网上试试！|unstyled|141288|.,\.&,-+#+Stack+will+be+show+as+[],+with+L+being+our+list.
.+++++++#+Duplicate+array+[L+L]
+,++++++#+Size+of+top+element+[L+N]
++\+++++#+Swap+the+positions+of+the+top+two+elements+[N+L]
+++.&+++#+Listwise+OR+(remove+duplicates)+[N+L&]
+++++,++#+Size+of+top+elements+(should+be+1+lesser)+[N+N-1?]
++++++-+#+Difference

Output+is+1+if+TRUE.+Any+other+result+is+FALSE.|entityMap|0|LINK|mutability|MUTABLE|url|http://www.golfscript.com/golfscript/|1|https://tio.run/##S8/PSStOLsosKPkfbahgqGCqYKJgHPtfTydGT01H9/9/AA^0|0|A|0|0|0|0|6|1|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|11|8|@]|9|@$A|12|B|13|1|14]]|C|$]]|$1|L|3|M|5|F|7|15|8|@]|9|@]|C|$G|H]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]]]

<h1><a href="http://www.golfscript.com/golfscript/" rel="nofollow noreferrer">GolfScript</a>, 7 bytes</h1>

<pre><code>.,\.&amp;,-
</code></pre>

<p><a href="https://tio.run/##S8/PSStOLsosKPkfbahgqGCqYKJgHPtfTydGT01H9/9/AA" rel="nofollow noreferrer" title="GolfScript – Try It Online">Try it online!</a></p>

<pre><code>.,\.&amp;,- # Stack will be show as [], with L being our list.
.       # Duplicate array [L L]
 ,      # Size of top element [L N]
  \     # Swap the positions of the top two elements [N L]
   .&amp;   # Listwise OR (remove duplicates) [N L&amp;]
     ,  # Size of top elements (should be 1 lesser) [N N-1?]
      - # Difference

Output is 1 if TRUE. Any other result is FALSE.
</code></pre>


blocks|key|1278760|text|因子，25字节|type|header-two|depth|inlineStyleRanges|entityRanges|offset|length|data|1278761|[+duplicates+length+1+=+]|code-block|syntax|javascript|1278762|在网上试试！|unstyled|1278763|解释|1278764|它是一个引号(匿名函数)，它接受一个序列作为输入，并留下一个布尔值作为输出。当这个引号被调用时，假设{+1+6+3+4+4+7+9+}在数据堆栈的顶部.|style|CODE|1278765|duplicates获得重复值的列表。堆栈：{+4+}|unordered-list-item|1278766|length得到长度。堆栈：1|1278767|1将1推到堆栈中。堆栈：1+1|1278768|如果数据堆栈上的前两个对象相等，则=返回t，否则返回f。堆栈：t|entityMap|0|LINK|mutability|MUTABLE|url|https://factorcode.org/|1|https://tio.run/##VU9NC8IwDL33V8Q/IK5@oeJZvHgRT@Kh1MyN1Vrb7DDGfnuNY8qaQMh7vJdHcqXp5ePlfDwdtlCht2ggIAUe7xqtxgDOI1HjfGkJdkK0ArgmQL6moulBCxl3999lglYwhwX3GjbMDu5cmYA/92ykTi9l/bUxliMshyyZZH/Tlsx08Qr32plSK@I3DNoHFazYwy0@lYNASlfT@AE^0|0|2|0|0|0|0|6|1|0|0|1E|H|0|0|A|M|5|0|0|6|E|1|0|0|1|2|1|C|3|0|H|1|K|1|Q|1|V|1^^$0|@$1|2|3|4|5|6|7|19|8|@]|9|@$A|1A|B|1B|1|1C]]|C|$]]|$1|D|3|E|5|F|7|1D|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|K|7|1E|8|@]|9|@$A|1F|B|1G|1|1H]]|C|$]]|$1|L|3|M|5|6|7|1I|8|@]|9|@]|C|$]]|$1|N|3|O|5|K|7|1J|8|@$A|1K|B|1L|P|Q]]|9|@]|C|$]]|$1|R|3|S|5|T|7|1M|8|@$A|1N|B|1O|P|Q]|$A|1P|B|1Q|P|Q]]|9|@]|C|$]]|$1|U|3|V|5|T|7|1R|8|@$A|1S|B|1T|P|Q]|$A|1U|B|1V|P|Q]]|9|@]|C|$]]|$1|W|3|X|5|T|7|1W|8|@$A|1X|B|1Y|P|Q]|$A|1Z|B|20|P|Q]|$A|21|B|22|P|Q]]|9|@]|C|$]]|$1|Y|3|Z|5|T|7|23|8|@$A|24|B|25|P|Q]|$A|26|B|27|P|Q]|$A|28|B|29|P|Q]|$A|2A|B|2B|P|Q]]|9|@]|C|$]]]|10|$11|$5|12|13|14|C|$15|16]]|17|$5|12|13|14|C|$15|18]]]]

<h1><a href="https://factorcode.org/" rel="nofollow noreferrer">Factor</a>, 25 bytes</h1>
<pre><code>[ duplicates length 1 = ]
</code></pre>
<p><a href="https://tio.run/##VU9NC8IwDL33V8Q/IK5@oeJZvHgRT@Kh1MyN1Vrb7DDGfnuNY8qaQMh7vJdHcqXp5ePlfDwdtlCht2ggIAUe7xqtxgDOI1HjfGkJdkK0ArgmQL6moulBCxl3999lglYwhwX3GjbMDu5cmYA/92ykTi9l/bUxliMshyyZZH/Tlsx08Qr32plSK@I3DNoHFazYwy0@lYNASlfT@AE" rel="nofollow noreferrer" title="Factor – Try It Online">Try it online!</a></p>
<h2>Explanation</h2>
<p>It's a quotation (anonymous function) that takes a sequence as input and leaves a boolean as output. Assuming <code>{ 1 6 3 4 4 7 9 }</code> is on top of the data stack when this quotation is called...</p>
<ul>
<li><code>duplicates</code> Obtain a list of duplicate values. <strong>Stack:</strong> <code>{ 4 }</code></li>
<li><code>length</code> Get the length. <strong>Stack:</strong> <code>1</code></li>
<li><code>1</code> Push <code>1</code> to the stack. <strong>Stack:</strong> <code>1 1</code></li>
<li><code>=</code> Return <code>t</code> if the top two objects on the data stack are equal, otherwise return <code>f</code>. <strong>Stack:</strong> <code>t</code></li>
</ul>


<p>Given a nonempty finite list of integers, output a <em>truthy</em> value if there are exactly two equal entries and all other entries are distinct, and a <em>falsey</em> value otherwise.</p>
<h3>Examples</h3>
<pre><code>truthy:
[1,1]
[1,2,1]
[1,6,3,4,4,7,9]
 
falsey:
[0]
[1,1,1]
[1,1,1,2]
[1,1,2,2]
[2,1,2,1,2]
[1,2,3,4,5]
</code></pre>


In Search of a Soulmate

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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给定一个非空的有限整数列表，如果正好有两个相等的条目，并且所有其他条目都是不同的，则输出一个真值，否则输出一个falsey值。示例truthy:[1,1][1,2,1][1,6,3,4,4,7,9] falsey:[0][1,1,1][1,1,1,2][1,1,2,2][2,1,2,1,2][1,2,3,4,5]

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回答 32

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外壳，4字节

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哈斯克尔，34字节

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JavaScript (ES6)，30字节

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示例

回答 32

Code Golf用户

外壳，4字节

解释

Code Golf用户

哈斯克尔，34字节

Code Golf用户

JavaScript (ES6)，30字节

社区

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