title: Perl: remove a part of string after pattern
body: <p>I have strings like this: </p>
  
  <pre><code>trn_425374_1_94_-
  trn_12_1_200_+
  trn_2003_2_198_+
  </code></pre>
  
  <p>And I want to split all after the first number, like this: </p>
  
  <pre><code>trn_425374
  trn_12
  trn_2003
  </code></pre>
  
  <p>I tried the following code: </p>
  
  <pre><code>$string =~ s/(?&lt;=trn_\d)\d+//gi;
  </code></pre>
  
  <p>But returns the same as the input. I have been following examples of similar questions but I don't know what I'm doing wrong. Any suggestion?</p>