How to extract numbers from a string and get an array of ints?

Question

I have a String variable (basically an English sentence with an unspecified number of numbers) and I'd like to extract all the numbers into an array of integers. I was wondering whether there was a quick solution with regular expressions?

---

I used Sean's solution and changed it slightly:

LinkedList<String> numbers = new LinkedList<String>();  Pattern p = Pattern.compile("\\d+"); Matcher m = p.matcher(line);  while (m.find()) {    numbers.add(m.group()); } 

Answer 1

Pattern p = Pattern.compile("-?\\d+"); Matcher m = p.matcher("There are more than -2 and less than 12 numbers here"); while (m.find()) {   System.out.println(m.group()); } 

... prints -2 and 12.

---

-? matches a leading negative sign -- optionally. \d matches a digit, and we need to write \ as \\ in a Java String though. So, \d+ matches 1 or more digits.

Answer 2

What about to use replaceAll java.lang.String method:

    String str = "qwerty-1qwerty-2 455 f0gfg 4";           str = str.replaceAll("[^-?0-9]+", " ");      System.out.println(Arrays.asList(str.trim().split(" "))); 

Output:

[-1, -2, 455, 0, 4] 

---

Description

[^-?0-9]+ 

• [ and ] delimites a set of characters to be single matched, i.e., only one time in any order
• ^ Special identifier used in the beginning of the set, used to indicate to match all characters not present in the delimited set, instead of all characters present in the set.
• + Between one and unlimited times, as many times as possible, giving back as needed
• -? One of the characters “-” and “?”
• 0-9 A character in the range between “0” and “9”