title: Using split(":") to get numbers from a string but I keep missing the first number
body: <p>I need to extract 2 numbers from several strings.</p>
  <p>This is an example and the code i am using:</p>
  <pre><code>data = 'Ant Graph first exam is :2 and the score after the second exam is :10'
  print ([int (s) for s in data.split(&quot;:&quot;) if s.isdigit()])
  </code></pre>
  <p>output [10]</p>
  <p>but if I remove the : and change a bit the code:</p>
  <pre><code>data = 'Ant Graph first exam is 2 and the score after the second exam is 10'
  print ([int (s) for s in data.split(&quot; &quot;) if s.isdigit()])
  </code></pre>
  <p>output [2, 10]</p>
  <p>Why in the first case do I miss the number 2?</p>