title: How to drop some observations based on the value of one variable in R?
body: <p>I have a dataset when I have three variables which can take the following values <code>-2, -1, 0, 1, 2, 3, 4, 5</code>
  For some reason, I only want to work with these variables when the observations are equal to <code>1, 2, 3, 4 or 5</code>. In other way, I want to drop observations when <code>var1/var2/var3=-2, -1 or 0</code>
  I know in Stata this is made with the command <code>DROP</code> (<code>drop if var1 == 0 / drop if var1&lt;0...</code>). Is there a similar equivalent in R? Thank you</p>