title: Extracting decimal numbers from a string
body: <p>I have a string such as <code>"3.1 ml"</code> or <code>"abc 3.1 xywazw"</code></p>
  
  <p>I'd like to extract <code>"3.1"</code> from this string. I have found many questions on stackoverflow about the extraction of numbers from a character string, but no solution works for the case of decimal numbers.</p>