title: How to know if its findable a value thats in a column in another column?
body: <p>I have two large databases, but I want to know how much of the data its already in the other, those values are random in the rows, so I need a filter that indícates what of the values in a df1$column are in the df2$column.</p>
  <p>For example, lets Think this like vectors.
  I have two vectors</p>
  <pre><code>a=c(&quot;q&quot;,&quot;w&quot;,&quot;e&quot;,&quot;r&quot;,&quot;t&quot;,&quot;y&quot;,&quot;u&quot;,&quot;i&quot;,&quot;o&quot;)
  b=c(&quot;o&quot;,&quot;u&quot;,&quot;y&quot;,&quot;t&quot;,&quot;r&quot;,&quot;e&quot;,&quot;w&quot;,&quot;q&quot;,&quot;a&quot;)
  </code></pre>
  <p>I want an output thats says the ones from b that are NOT in a, for example</p>
  <pre><code>&gt;&quot;i&quot;
  </code></pre>
  <p>Hope this is understandable</p>