I read a text file and put the data into an ArrayList of String.
The data is like
China 12351235123 Korea 123532523 USA 12341235123
I just need those integer data as an integer to find the first digit of the integers. I know how to find the first digit, but I don't know how I can pick up only the integer data.
I am assuming that your ArrayList is of type String. replaceAll() will take out anything that isn't a number(0-9)
ArrayList<String> countrys = new ArrayList<String>();
countrys.add("China 12351235123");
countrys.add("Korea 123532523");
countrys.add("USA 12341235123");
for(String c:countrys){
String number = c.replaceAll("[^0-9]", "");
System.out.println(number);
}
Try this :
// Creation of ArrayList of string
ArrayList<String> obj = new ArrayList<String>();
// arrayList of string
obj.add("China 12351235123");
obj.add("Korea 123532523");
obj.add("USA 12341235123");
Iterator<String> iterator = obj.iterator();
String str;
String[] split_str;
long value;
while (iterator.hasNext()) {
str = iterator.next().toString();
split_str = str.split(" ");
String split_2 = split_str[1];
value = Long.parseLong(split_2);
System.out.println(value);
}
You can use Regex as SLY suggested, or you can go over your list and split the object into two parts: 'country' and 'number' using:
for(String s : array){
String[] parts = s.split(" ");
long number = Long.parseLong(parts[1]);
System.out.println(number);
}
NOTE: the invariant is that each element contains two parts with the delimiter 'white space', and the second part is a number.
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
public static void main(String[] args) {
List<Long> longList = new ArrayList<Long>();
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);
}
