title: Split string column based on number of characters
body: <p>I have the following column in a dataframe:</p>
  
  <pre><code>columnA
  EUR590
  USD680
  EUR10000,9
  USD40
  </code></pre>
  
  <p>how can i split it based on the first three characters, that the dataframe looks like:</p>
  
  <pre><code>columnA columnB
  590     EUR
  680     USD
  10000,9  EUR
  40       USD
  </code></pre>