title: Regular expression to extract (only) the first numeric value
body: <p>How could I get only the first number from the strings below?<br>
  Regular expression should stop at space or first non-numeric character.</p>
  
  <p>Examples:<br>
  6x2mL<br>
  7 x 5mL<br>
  100Subunits<br>
  2*5Kg<br></p>