title: How to get the rows with none values in R
body: <p>I'm learning R now.So i have a question. I use the the titanic dataset.Now i want to get the rows with none or null values by column Embarked.
  The dataset is like that with column Embarked. And we have 2 rows with None value by Embarked</p>
  <pre><code>  :  2   
   C:168   
   Q: 77   
   S:644
  </code></pre>
  <p>i tried with this</p>
  <pre><code>titanic[titanic$Embarked==&quot;&quot;]
  
  </code></pre>
  <p>i got this error</p>
  <p>Error in <code>[.data.frame</code>(titanic, titanic$Embarked == &quot;&quot;) :
  undefined columns selected.</p>
  <p>Could someone help me this one.Thank you so much</p>