blocks|key|1149915|text|在您的代码Object.values中，返回源的值为"Capulet"，而在for循环中，您将源等效为数组(源是对象)，这就是为什么测试是未定义的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1149916|​|1149917|function+whatIsInAName(collection,+source)+{
++//+What's+in+a+name?
++var+arr+=+[];
++//+Only+change+ode+below+this+line
++
++
++var+test+=+Object.keys(source);//changes+values+to+keys
++console.log(test);
++for(var+i+=+0;+i+<+collection.length;+i%2B%2B)+{
++++if+(collection[i][test]+===+source[test]){+//change+how+you+are+accessing+test
++++++arr.push(collection[i]);
++++}
++}

++//+Only+change+code+above+this+line
++//arr+=+collection[0].last;
++console.log(arr);
++return+arr;+
}

whatIsInAName([{+first:+"Romeo",+last:+"Montague"+},+{+first:+"Mercutio",+
last:+null+},+{+first:+"Tybalt",+last:+"Capulet"+}],+{+last:+"Capulet"+});|code-block|syntax|javascript|1149918|1149919|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$G|H]]|$1|I|3|C|5|6|7|O|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|K|$]]

<p>In your code Object.values returning the value of source that is "Capulet", whereas in for loop you are equating source as an array(source is object), that is why, test is undefined</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>function whatIsInAName(collection, source) {
  // What's in a name?
  var arr = [];
  // Only change ode below this line
  
  
  var test = Object.keys(source);//changes values to keys
  console.log(test);
  for(var i = 0; i &lt; collection.length; i++) {
    if (collection[i][test] === source[test]){ //change how you are accessing test
      arr.push(collection[i]);
    }
  }

  // Only change code above this line
  //arr = collection[0].last;
  console.log(arr);
  return arr; 
}

whatIsInAName([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", 
last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });</code></pre>
</div>
</div>
</p>


blocks|key|640426|text|要传入的对象没有名为test的密钥。如果您试图使用您在这里创建的变量var+test+=+Object.values(source);，这将无法工作，因为test无论如何都是一个数组。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|640427|你可以尝试这样的方法：|640428|if+(collection[i][test]+===+source[0][test])|code-block|syntax|javascript|640429|但我认为这也行不通，因为根据test的文档，Object.values()的值应该是Capulet|640430|entityMap^0|A|4|Y|X|25|4|0|0|0|E|4|M|F|16|7|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|Z|8|@$9|10|A|11|B|C]|$9|12|A|13|B|C]|$9|14|A|15|B|C]]|D|@]|E|$]]|$1|O|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|P|$]]

<p>The objects you're passing in have no key named <code>test</code>. If you're trying to use the variable you created here <code>var test = Object.values(source);</code>, this won't work because <code>test</code> is an array anyways.</p>

<p>You could try something like: </p>

<pre><code>if (collection[i][test] === source[0][test])
</code></pre>

<p>but I don't think that will work either because <code>test</code> should have the value of <code>Capulet</code> according to documentation for <code>Object.values()</code></p>


blocks|key|3390131|text|尝尝这个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3390132|function+whatIsInAName(collection,+source)+{
++var+arr+=+[];
++var+keys+=+Object.keys(source);

++for(var+i+=+0;+i+<+collection.length;+i%2B%2B)+{
++++++var+item+=+collection[i];
++++++var+all+=+true;
++++++for(var+k+=+0;+k+<+keys.length;+k%2B%2B){
++++++++++var+key+=+keys[k];
++++++++++if(item[key]+!=+source[key]){
++++++++++++all+=+false;
++++++++++++break;
++++++++++}
++++++}
++++++if(all){
++++++++++arr.push(item)
++++++}
++}

++return+arr;+
}|code-block|syntax|javascript|3390133|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>try this.</p>

<pre><code>function whatIsInAName(collection, source) {
  var arr = [];
  var keys = Object.keys(source);

  for(var i = 0; i &lt; collection.length; i++) {
      var item = collection[i];
      var all = true;
      for(var k = 0; k &lt; keys.length; k++){
          var key = keys[k];
          if(item[key] != source[key]){
            all = false;
            break;
          }
      }
      if(all){
          arr.push(item)
      }
  }

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


<p>I have been looking at this and reading for a while but can't seem to understand.  I am sure it is simple but I can not figure out why I can access the data in collection.  I get an error of </p>

<blockquote>
  <p>test undefined</p>
</blockquote>

<p>If I move outside of the for loop I can access it just fine.  I am obviously missing something simple. Any help would be great.</p>

<pre><code>function whatIsInAName(collection, source) {
  // What's in a name?
  var arr = [];
  // Only change ode below this line
  var test = Object.values(source);

  for(var i = 0; i &lt; collection.length; i++) {
    if (collection[i].test === source[0].test){
      arr[i] = collection[i];
    }
  }

  // Only change code above this line
  //arr = collection[0].last;
  return arr; 
}

whatIsInAName([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", 
last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });
</code></pre>


Accessing data in an array

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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我一直在看这个，阅读了一段时间，但似乎无法理解。我确信这是简单的，但我不知道为什么我可以访问收集的数据。我得到了一个错误测试未定义如果我在for循环之外移动，我可以很好地访问它。我显然错过了一些简单的东西。任何帮助都会很好。function whatIsInAName(collection, source) {  //...

问访问数组中的数据
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