regpexpr()</code> and <code>substr()</code>.</p></li>
<li><p>Base functions use arguments (like <code>perl</code>,
<code>fixed</code>, and <code>ignore.case</code>) to control how the
pattern is interpreted. To avoid dependence between arguments, stringr
instead uses helper functions (like <code>fixed()</code>,
<code>regex()</code>, and <code>coll()</code>).</p></li>
</ol>
<p>Next we’ll walk through each of the functions, noting the
similarities and important differences. These examples are adapted from
t