title: Filter data frame rows based on values in vector
body: <p>What is the best way to filter rows from data frame when the values to be deleted are stored in a vector? In my case I have a column with dates and want to remove several dates.</p>
  <p>I know how to delete rows corresponding to <em>one</em> day, using <code>!=</code>, e.g.:</p>
  <pre><code>m[m$date != &quot;01/31/11&quot;, ]
  </code></pre>
  <p>To remove several dates, specified in a vector, I tried:</p>
  <pre><code>m[m$date != c(&quot;01/31/11&quot;, &quot;01/30/11&quot;), ]
  </code></pre>
  <p>However, this generates a warning message:</p>
  <pre><code>Warning message:
  In `!=.default`(m$date, c(&quot;01/31/11&quot;, &quot;01/30/11&quot;)) :
  longer object length is not a multiple of shorter object length
  Calls: [ ... [.data.frame -&gt; Ops.dates -&gt; NextMethod -&gt; Ops.times -&gt; NextMethod
  </code></pre>
  <p>What is the correct way to apply a filter based on multiple values?</p>