title: R: used `which` statement with multiple conditions = how to treat result?
body: <p>Hey I am new to R and I would like to find out, which <strong>city</strong> has the highest T AND the highest SO2-value.
  The dataset is data(&quot;USairpollution&quot;).</p>
  <p>First I asked:</p>
  <pre><code>max(x$SO2)
  rownames(x)[which(x$SO2&gt;=110)]
  max(x$temp)
  rownames(x)[which(x$temp&gt;=75.5)]
  </code></pre>
  <p>combined it after long trial and error to:</p>
  <pre><code>maxT_maxSO2=(which(x == max(x$SO2)) &amp; (x == max(x$temp)))
  </code></pre>
  <p>Now, my question is: I have now a dataframe with one single TRUE.</p>
  <ol>
  <li>is this the correct city?</li>
  <li>how can I find out the name? (Apart from visually checking the dataframe)</li>
  </ol>