Question

In the application there is a string in the following format:

String elements = “[11, john,][23, Adam,][88, Angie,]…” (… means there are more elements in the string)

From the given string I have to create an ArrayList for name IDs (11, 23, 88, …) and ArrayList for names (john, Adam, Angie, …)

I created two methods:

private int getItemID(int listLocation, String inputString){
    int indexBeginning = inputString.indexOf("[", listLocation) + 1;
    int indexEnd = inputString.indexOf(",", listLocation) - 1;
    String sID = inputString.substring(indexBeginning, indexEnd);
    int result = Integer.parseInt(sID);
    return result;
}

private String getItemName(int listLocation, String inputString){
    int indexBeginning = inputString.indexOf(" ", listLocation) + 1;
    int indexEnd = inputString.indexOf(",", indexBeginning) - 1;
    String result = inputString.substring(indexBeginning, indexEnd);
    return result;
}

and intend to use these two methods in the method parseArrayString(String inputString), which I haven’t written yet but would work the following way:

private void parseCommunityList(String inputString){
        int currentLocation = 0;
        int itemsCount = count the number of "[" characters in the string
        for(int i = 0; i < itemsCount; i++)
        {
               currentLocation = get the location of the (i)th character "[" in the string;
               String name = getItemName(currentLocation, inputString);
               int ID = getItemID(currentLocation, inputString);
               nameArray.Add(name);
               idArray,Add(ID);
        }

    }

I would appreciate if anyone of you could suggest any simpler way to create two ArrayLists from the given string.

Thanks!

Answer 1

I would suggest using a regular expression, capturing the elements you want using groups. The example below creates a list of Person objects instead of individual lists of Strings – encapsulating the data as other posters have suggested:

    List<Person> people = new ArrayList<Person>();

    String regexpStr = "(\\[([0-9]+),\\s*([0-9a-zA-Z]+),\\])";
    String inputData = "[11, john,][23, Adam,][88, Angie,]";

    Pattern regexp = Pattern.compile(regexpStr);
    Matcher matcher = regexp.matcher(inputData);
    while (matcher.find()) {
        MatchResult result = matcher.toMatchResult();

        String id = result.group(2);
        String name = result.group(3);

        Person person = new Person(Long.valueOf(id), name);
        people.add(person);
    }

And a simple class to encapsulate the data:

public class Person {
    private Long id;
    private String name;

    public Person(Long id, String name) {
        this.id = id;
        this.name = name;
    }

    public Long getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    // TODO equals, toString, hashcode...
}