title: How do I select a substring using a regexp in robot framework
body: <p>In the Robot Framework library called String, there are several keywords that allow us to use a regexp to manipulate a string, but these manipulations don't seem to include selecting a substring from a string.</p>
  
  <p>To clarify, what I intend is to have a price, i.e. <code>€ 1234,00</code> from which I would like to select only the 4 primary digits, meaning I am left with <code>1234</code> (which I will convert to an int for use in validation calculations). I have a regexp which will allow me to do that, which is as follows: </p>
  
  <p><code>(\d+)[\.\,]</code></p>
  
  <p>If I use <code>Remove String Using Regexp</code> with this regexp I will be left with exactly what I tried to remove. If I use <code>Get Lines Matching Regexp</code>, I will get the entire line rather than just the result I wanted, and if I use <code>Get Regexp Matches</code> I will get the right result except it will be in a list, which I will then have to manipulate again so that doesn't seem optimal.</p>
  
  <p>Did I simply miss the keyword that will allow me to do this or am I forced to write my own custom keyword that will let me do this? I am slightly amazed that this functionality doesn't seem to be available, as this is the first use case I would think of when I think of using a regexp with a string...</p>