blocks|key|1574376|text|您的问题是，即使在从数组中找到与传递给函数的名称匹配的名称之后，for循环仍将继续循环到x数组中的其他名称上。这意味着在for循环的进一步迭代中，代码的else块将运行并覆盖以前设置的txt值。这就是"Sam“工作的原因，因为这是x数组中的姓，因此txt不会被for循环的进一步迭代覆盖。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1574377|关于您的代码，另一件需要注意的事情是循环不应用于迭代数组。它可能导致不必要的值被访问，因为它不只是遍历数组的索引，而是其他属性。|1574378|这么说，你的代码设计过度了。当前，您的对象存储键值对.关键是名称，价值是国家。对于对象中的每个键，可以使用括号表示法访问它。|1574379|console.log(GUEST_LIST["Randy"]);+//+Germany|code-block|syntax|javascript|1574380|考虑到这个想法，您的name变量可以用作对象的键，然后可以用于获取国家。如果GUEST_LIST对象不包含您的键(即:尝试从对象访问键时返回的值为falsy)，则可以返回默认的"Hi!+I'm+a+guest"文本：|1574381|​|1574382|const+GUEST_LIST+=+{
++Randy:+"Germany",
++Karla:+"France",
++Wendy:+"Japan",
++Norman:+"England",
++Sam:+"Argentina"
};

function+greeting(name)+{
++const+country+=+GUEST_LIST[name];
++if(country)
++++return+"Hi+I'm+"%2Bname+%2B",+and+I'm+from+"+%2Bcountry;+
++else
++++return+"Hi!+I'm+a+guest";
}
console.log(greeting("Randy"));|1574383|1574384|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/500504/why-is-using-for-in-for-array-iteration-a-bad-idea|1|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_accessors#bracket_notation^0|18|1|24|4|2K|3|37|1|3G|3|0|I|A|0|0|1H|5|1|0|0|A|4|2G|H|0|0|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]|$9|1E|A|1F|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1G|8|@]|D|@$9|1H|A|1I|1|1J]]|E|$]]|$1|H|3|I|5|6|7|1K|8|@]|D|@$9|1L|A|1M|1|1N]]|E|$]]|$1|J|3|K|5|L|7|1O|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|1P|8|@$9|1Q|A|1R|B|C]|$9|1S|A|1T|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1U|8|@]|D|@]|E|$]]|$1|S|3|T|5|L|7|1V|8|@]|D|@]|E|$M|N]]|$1|U|3|R|5|6|7|1W|8|@]|D|@]|E|$]]|$1|V|3|-4|5|6|7|1X|8|@]|D|@]|E|$]]]|W|$X|$5|Y|Z|10|E|$11|12]]|13|$5|Y|Z|10|E|$11|14]]]]

<p>Your issue is that your for loop will continue to loop over the other names in your <code>x</code> array even after you have found a name from your array that matches the name you passed into your function. That means on further iterations of your for loop, your <code>else</code> block of your code will run and overwrite the value of <code>txt</code> previously set. That's why &quot;Sam&quot; works, as that's the last name in your <code>x</code> array, and so <code>txt</code> doesn't get overwritten by further iterations of your for loop.</p>
<p>Another thing to note about your code, a <a href="https://stackoverflow.com/questions/500504/why-is-using-for-in-for-array-iteration-a-bad-idea"><code>for...in</code> loop shouldn't be used to iterate over an array</a>. It can lead to unwanted values being accessed, as it doesn't just loop over the indices of your array, but rather other properties.</p>
<p>With that being said, you're over-engineering your code. Currently, your object stores key-value pairs. The key is the name and the value is the country. For each key in your object, you can access it using <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_accessors#bracket_notation" rel="nofollow noreferrer">bracket-notation</a>:</p>
<pre class="lang-js prettyprint-override"><code>console.log(GUEST_LIST[&quot;Randy&quot;]); // Germany
</code></pre>
<p>With that idea in mind, your <code>name</code> variable can be used as the key for your object, which can then be used to obtain the country. If the GUEST_LIST object doesn't contain your key (ie: the value returned by trying to access the key from your object is falsy), then you can return your default <code>&quot;Hi! I'm a guest&quot;</code> text:</p>
<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>const GUEST_LIST = {
  Randy: "Germany",
  Karla: "France",
  Wendy: "Japan",
  Norman: "England",
  Sam: "Argentina"
};

function greeting(name) {
  const country = GUEST_LIST[name];
  if(country)
    return "Hi I'm "+name +", and I'm from " +country; 
  else
    return "Hi! I'm a guest";
}
console.log(greeting("Randy"));</code></pre>
</div>
</div>
</p>


blocks|key|1574394|text|为了理解我的意思，这里是您代码的工作版本。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1574395|for+(let+i+in+x)
{
++++if+(name+===+x[i])
++++++{
++++++++txt+=+"Hi+I'm+"%2Bx[i]+%2B",+and+I'm+from+"+%2Barray[i];
++++++++break;+//+<----+stop+the+loop+here+when+you+find+a+match
++++++}
++++else
++++++{
++++++++txt+=+"Hi!+I'm+a+guest";
++++++}

++}
+++return+txt;
}|code-block|syntax|javascript|1574396|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

<p>To appreciate what I mean here is the working version of your code.</p>
<pre><code>for (let i in x)
{
    if (name === x[i])
      {
        txt = &quot;Hi I'm &quot;+x[i] +&quot;, and I'm from &quot; +array[i];
        break; // &lt;---- stop the loop here when you find a match
      }
    else
      {
        txt = &quot;Hi! I'm a guest&quot;;
      }

  }
   return txt;
}
</code></pre>


blocks|key|1574411|text|简单易懂，短小：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1574412|const+GUEST_LIST+=+{
++++Randy:+"Germany",
++++Karla:+"France",
++++Wendy:+"Japan",
++++Norman:+"England",
++++Sam:+"Argentina"
}


function+greeting(name){
++++return+(GUEST_LIST[name])+?+
+++++`Hi,+I'm+${name}+and+I'm+from+${GUEST_LIST[name]}`+:+
+++++`Hi!+I'm+a+guest`
}


console.log(greeting("Randy"))|code-block|syntax|javascript|1574413|​|1574414|entityMap^0|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]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

<p>Simple to read and short:
<div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>const GUEST_LIST = {
    Randy: "Germany",
    Karla: "France",
    Wendy: "Japan",
    Norman: "England",
    Sam: "Argentina"
}


function greeting(name){
    return (GUEST_LIST[name]) ? 
     `Hi, I'm ${name} and I'm from ${GUEST_LIST[name]}` : 
     `Hi! I'm a guest`
}


console.log(greeting("Randy"))</code></pre>
</div>
</div>
</p>


<p>Could someone help me with this code, I'm trying to write a function that takes in a name from an object and returns a name tag :
<strong>&quot;Hi! I'm [name], and I'm from [country].&quot;</strong></p>
<p>I've tried this code</p>
<pre><code>const GUEST_LIST = {
    Randy: &quot;Germany&quot;,
    Karla: &quot;France&quot;,
    Wendy: &quot;Japan&quot;,
    Norman: &quot;England&quot;,
    Sam: &quot;Argentina&quot;
}

function greeting(name) {
  var x = Object.keys(GUEST_LIST);
  const array = Object.keys(GUEST_LIST)
    .map(function(key) {
        return GUEST_LIST[key];
    });
  
  
  var txt =&quot;&quot;;
  for (let i in x)
    {
      if (name === x[i])
        {
          txt = &quot;Hi I'm &quot;+x[i] +&quot;, and I'm from &quot; +array[i];  
        }
      else
        {
          txt = &quot;Hi! I'm a guest&quot;;
        }
      
    }
     return txt;
}
console.log(greeting(&quot;Randy&quot;))
</code></pre>
<p>but it always returns <strong>&quot;Hi! I'm a guest&quot;</strong> except when I type <em>Sam</em>,</p>


if else statement javascript returns false statement

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。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

有人能帮我完成这段代码吗?我正在编写一个函数，它从一个对象中获取一个名称，并返回一个名称标签：“嗨！我是名字，我来自乡下。”。我试过这段代码const GUEST_LIST = {    Randy: "Germany",    Karla: "France",    Wendy: "Japan",    Norman...

问如果else语句javascript返回false语句
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如果else语句javascript返回false语句EN