How to pick up only integer data from an ArrayList of String

Question

I read a text file and put the data into an ArrayList of String.

The data is like

China 12351235123 Korea 123532523 USA 1234123         


        

Answer 1

You can use regex and would be careful that not all that numbers can be in a integer range... so there for the list of longs in the code below

Example:

public static void main(String[] args) {
    List longList = new ArrayList();
    Pattern pattern = Pattern.compile("\\w+([0-9]+)");// regex pattern
    for (String string : listOfCountriesAndNumbers) {
        Matcher matcher = pattern.matcher(string);
        for (int i = 0; i < matcher.groupCount(); i++) {
            matcher.find();
            longList.add(Long.parseLong(matcher.group()));
        }
    }
    System.out.println(longList);
}