title: Find numbers in string using Golang regexp
body: <p>I want to find all numbers in a string with the following code:</p>
  
  <pre><code>re:=regexp.MustCompile("[0-9]+")
  fmt.Println(re.FindAllString("abc123def", 0))
  </code></pre>
  
  <p>I also tried adding delimiters to the regex, using a positive number as second parameter for <code>FindAllString</code>, using a numbers only string like "123" as first parameter...</p>
  
  <p>But the output is always <code>[]</code></p>
  
  <p>I seem to miss something about how regular expressions work in Go, but cannot wrap my head around it. Is <code>[0-9]+</code> not a valid expression?</p>