Java - Split String by Number and Letters

Question

So I have, for example, a string such as this C3H20IO

What I wanna do is split this string so I get the following:

Array1 = {C,H,I,O}
Ar         


        

Answer 1

An approach without REGEX and data stored using ArrayList:

String s = "C3H20IO";

char Chem = '-';
String val = "";
boolean isFisrt = true;
List chemList = new ArrayList();
List weightList = new ArrayList();
for (char c : s.toCharArray()) {
    if (Character.isLetter(c)) {
        if (!isFisrt) {
            chemList.add(Chem);
            weightList.add(Integer.valueOf(val.equals("") ? "1" : val));
            val = "";
        }
        Chem = c;
    } else if (Character.isDigit(c)) {
        val += c;
    } 
    isFisrt = false;
}
chemList.add(Chem);
weightList.add(Integer.valueOf(val.equals("") ? "1" : val));

System.out.println(chemList);
System.out.println(weightList);

OUTPUT:

[C, H, I, O]
[3, 20, 1, 1]