title: Removing NAs from column while calculating the length of it
body: <p>So i've got a column in dataframe for 237 different pulses, and from those i gotta take pulses that are over 100 and less than 45, and see how many of them there are. I know that i can get the lenght of that with</p>
  
  <pre><code>length(survey$Pulse[survey$Pulse &gt; 100 | survey$Pulse &lt; 45])
  </code></pre>
  
  <p>However there are NA values in the column and i got no idea how to remove those from the lenght.</p>
  
  <p>If you need more info ill try to provide but the only thing i dont know how to do is removing NA values from the column.</p>
  
  <p>I know i could use <code>na.rm=TRUE</code> but i got no idea how to implement it to the line.</p>