d$lastName, &quot;label&quot;) &lt;- &quot;Last name&quot;

attr(pd$presidencyYears, &quot;label&quot;) &lt;- &quot;Duration of presidency&quot;

attr(pd$orderOfPresidency, &quot;label&quot;) &lt;- &quot;Presidency order&quot;

attr(pd$birthday, &quot;label&quot;) &lt;- &quot;Date of birth&quot;

attr(pd$dateOfDeath, &quot;label&quot;) &lt;- &quot;Date of death&quot;

attr(pd$stateOfBirth, &quot;label&quot;) &lt;- &quot;Birth state of the president&quot;

attr(pd$sex, &quot;label&quot;) &lt;- &quot;Sex&quot