title: Find an integer followed by a string with Golang regexp
body: <p>I want to find an integer which is followed by the term "Price: ", whether in the output, I only need to print the integer which must be excluded the term "Price: ".
  Right now, my code is like this and the output is [Price: 100], but I only need 100 in the output.</p>
  
  <pre><code>package main 
  
  import (
      "regexp"
      "fmt"
  )
  
  const str = "Some strings. Price: 100$. Some strings123"
  
  func main() {
      re := regexp.MustCompile("Price:[[:space:]][0-9]+")
      fmt.Println(re.FindAllString(str, -1))
  } 
  </code></pre>