title: Why is integer(0) outputted when I use the which() function?
body: <p>I am trying to determine which variables in my V1 column have values in the V5 column that are in the range of 95-105 and also have values in the V6 column that are in the 7-13 range. I am using the which function and attempting to store the names of the variables in V1 under the variable x but I keep getting the output integer(0) or character(0) and I'm not sure what that means. An image of my code is attached below. </p>
  
  <p><a href="https://i.stack.imgur.com/KqJz2.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KqJz2.png" alt="enter image description here"></a></p>