title: Merge the values of a melt dataframe and another one
body: <p>Using a melt dataframe like this:</p>
  <pre><code>dframe1 &lt;- data.frame &lt;- data.frame(id = c(1,1,2), name = c(&quot;google&quot;, &quot;google&quot;, &quot;amazon&quot;))
  </code></pre>
  <p>and a second data frame which has the same id coloumn like this:</p>
  <pre><code>dframe2 &lt;- data.frame(id = c(1,2), mainnum = c(12.4, 32.1))
  </code></pre>
  <p>How is it possible to merge the two dataframes and receive this result:</p>
  <pre><code>data.frame &lt;- data.frame(id = c(1,1,2), name = c(&quot;google&quot;, &quot;google&quot;, &quot;amazon&quot;), mainnum = c(12.4, 12.4, 32.1))
  </code></pre>