title: Adding a column with consecutive numbers in R
body: <p>I apologize if this question is abhorrently simple, but I'm looking for a way to just add a column of consecutive integers to a data frame (if my data frame has 200 observations, for example, starting with 1 for the first observation, and ending with 200 on the last one). </p>
  
  <p>How can I do this?</p>