 columns <code>tab1$Industry</code> and <code>tab2$industry</code>. These two merged columns will be named <code>"countries"</code> and <code>"sector"</code> in the output, as requested by the user.</p></li>
<li><p>In case a <strong>vector</strong> is passed, each element is interpreted as a regular expression to be used for matching the columns to be merged. For example, the same order provided in the list example could be written as <code>c("countries"="Nation|COUNTRY", "sector"="[Ii]ndustry")</code>. Thi