title: R - Insert value into new row based on another dataframe
body: <p>Dataframe_1</p>
  
  <pre><code>    Name  Value
      a      4
      b      5
      c      7
      d      9
  </code></pre>
  
  <p>Dataframe_2</p>
  
  <pre><code>    Name Mass
      a     131
      c     140
      b     110
      d     90
  </code></pre>
  
  <p>I want the following result:</p>
  
  <pre><code>   Name  Value   Mass
     a      4      131
     b      5      110
     c      7      140
     d      9      90
  </code></pre>
  
  <p>I did this originally as the following but now I have dataframe_2 that I want to get the value from</p>
  
  <pre><code>   Dataframe_1$Mass &lt;- gsub("a", 131, Dataframe_1$Name)
  </code></pre>
  
  <p>Thank you for your help</p>