title: Add new column to dataframe depending on upper limit
body: <p>I have a dataset in which I want regarding to one of the num_values add new value from the other dataframe.</p>
  <p>Here's an example, create some df1</p>
  <pre><code>First.Name &lt;- c(&quot;John&quot;, &quot;Edgar&quot;, &quot;Walt&quot;, &quot;Jane&quot;)
  Second.Name &lt;- c(&quot;Doe&quot;, &quot;Poe&quot;, &quot;Whitman&quot;, &quot;Austen&quot;)
  num_value &lt;- runif(4,0,1.2)
  df1 &lt;- data.frame(First.Name, Second.Name, num_value)
  </code></pre>
  <p>which has this output</p>
  <pre><code> First.Name Second.Name  num_value
  1       John         Doe 0.08137931
  2      Edgar         Poe 0.30245512
  3       Walt     Whitman 0.62542554
  4       Jane      Austen 0.40573224
  </code></pre>
  <p>df2 is defined as</p>
  <pre><code>upper_boundary &lt;- seq(0,1.6,0.2)
  class_value &lt;- c(1:9)
  df2 &lt;- data.frame(upper_boundary, class_value)
  </code></pre>
  <p>and has it's output as</p>
  <pre><code>  upper_boundary class_value
  1            0.0           1
  2            0.2           2
  3            0.4           3
  4            0.6           4
  5            0.8           5
  6            1.0           6
  7            1.2           7
  8            1.4           8
  9            1.6           9
  </code></pre>
  <p>What I'd like to do is to add at the end of the first data frame class value from df2.
  Output should be something like</p>
  <pre><code>       First.Name Second.Name  num_value     class_value  
      1       John         Doe 0.08137931         2
      2      Edgar         Poe 0.30245512         3
      3       Walt     Whitman 0.62542554         5
      4       Jane      Austen 0.40573224         4
  </code></pre>
  <p>Thanks in advance</p>