title: R: Assign values to a new column based on values of another column where a condition is satisfied
body: <p>I want to create a new column in a data.frame where its value is equal to the value in another data.frame where a particular condition is satisfied between two columns in each data frame.</p>
  
  <p>The R pseudo-code being something like this:</p>
  
  <p><code>DF1$Activity &lt;- DF2$Activity where DF2$NAME == DF1$NAME</code></p>
  
  <p>In each data.frame values for <code>$NAME</code> are unique in the column.</p>