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

java arrays regex string
John Manak picture John Manak · Mar 2, 2010 · Viewed 256.5k times · Source

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

Sean Owen picture Sean Owen · Mar 2, 2010 
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.

Related questions

How do I declare and initialize an array in Java?

How do I declare and initialize an array in Java?

Read More
What's the simplest way to print a Java array?

In Java, arrays don't override toString(), so if you try to print one directly, you get the className + '@' + the hex of the hashCode of the array, as defined by Object.toString(): int[] intArray = new int[] {1, 2, 3, 4, 5}; System.out.println(…

Read More
How do I determine whether an array contains a particular value in Java?

I have a String[] with values like so: public static final String[] VALUES = new String[] {"AB","BC","CD","AE"}; Given String s, is there a good way of testing whether VALUES contains s?

Read More