title: pandas str extract use regex to select all letters from a string only returning 1st match - str extract or regex issue?
body: <p>In Pandas I have a dataframe column called TermNew containing the following lowercase strings (please ignore bullet points - I was having trouble formatting)</p>
  <p><strong>TermNew</strong></p>
  <ul>
  <li><p>999 years from 1/01/2001</p>
  </li>
  <li><p>999 years (less 20 days) from 20/11/2000</p>
  </li>
  <li><p>99 years from 1/10/1979</p>
  </li>
  <li><p>999 years from 1/01/1992</p>
  </li>
  </ul>
  <p>Im trying to extract all letter characters (a-z only, no digits, no whitespace, no () or /) from TermNew into a new column Termtext with these expected outcomes</p>
  <p><strong>Termtext</strong></p>
  <ul>
  <li>yearsfrom</li>
  <li>yearslessdaysfrom</li>
  <li>yearsfrom</li>
  <li>yearsfrom</li>
  </ul>
  <p>Ive tried the following but its only returning letters up to the first white space i.e.</p>
  <p><strong>leaseterm1['Termtext'] = leaseterm1['TermNew'].str.extract(r&quot;([a-z]+)&quot;)</strong></p>
  <p><strong>Outputs</strong></p>
  <ul>
  <li><p>years</p>
  </li>
  <li><p>years</p>
  </li>
  <li><p>years</p>
  </li>
  <li><p>years</p>
  </li>
  </ul>
  <p>In regex101 I can use the global flag to match all letters correctly <a href="https://www.regex101.com/r/JIuyEf/1" rel="nofollow noreferrer">See example </a></p>
  <p><strong>Questions</strong></p>
  <p><strong>1/ Is this a problem with str extract only finding the first match   or</strong></p>
  <p><strong>2/ Is this a regex problem - I havent included any form of global search past the 1st whitespace?</strong></p>
  <p><strong>Any suggestions gratefully received.   Thanks</strong></p>