title: Adding a sequence to every row of a column in R?
body: <p>I have two tables that I would like to combine in a certain way, however I have so far been unable to find a way as to how I should tackle this (I would say relatively easy?) problem.</p>
  
  <p>The situation can be simplified as follows:</p>
  
  <pre><code>dt1:
  1
  2
  3
  
  dt2:
  A
  B
  C
  D
  </code></pre>
  
  <p>My goal:</p>
  
  <pre><code>dt12:
  1 A
  1 B
  1 C
  1 D
  2 A
  2 B
  2 C
  2 D
  3 A
  3 B
  3 C
  3 D
  </code></pre>
  
  <p>I tried different things but I am starting to feel like I am overlooking something very basic. </p>