Convert day of week list to hyphenated String

Question

Is there any existing library that I use to convert a list of days of weeks into a hyphenated/concatenated String?

For example:

["Monday", "Tuesday", "Wednesday", "Friday"] would become "Monday - Wednesday, Friday"

The list will always contain unique days. So you'll never see ["Monday", "Monday", "Tuesday", ...].

Thanks!

SOLUTION

Thanks to kamoor1982's solution below

I had to make a few changes to his code to handle edge cases:

enum DayEnum {
    Monday(1),
    Tuesday(2),
    Wednesday(3),
    Thursday(4),
    Friday(5),
    Saturday(6),
    Sunday(7);

    private int value;

    DayEnum(int x) {
        this.value = x;
    }

    public int getValue() {
        return value;
    }
}
...
public static String concatenateDays(List<String> days) {

    // Null check
    if (days == null || days.isEmpty()) {
        return "";
    }

    // Sort list according to order it appears in calendar with Monday as starting day
    Collections.sort(days, new Comparator<String>() {
        @Override
        public int compare(String lhs, String rhs) {
            DayEnum lhsEnum = DayEnum.valueOf(lhs);
            DayEnum rhsEnum = DayEnum.valueOf(rhs);

            return lhsEnum.compareTo(rhsEnum);
        }
    });

    StringBuffer result = new StringBuffer(days.get(0));
    DayEnum valueOf = DayEnum.valueOf(result.toString());
    int previousIndex = valueOf.getValue();
    int length = days.size();

    for (int i = 1; i < days.size(); i++) {
        String day = days.get(i);
        if (previousIndex + 1 == DayEnum.valueOf(day).getValue()) {
            if (i == length - 1 || DayEnum.valueOf(day).getValue() + 1 != DayEnum.valueOf(days.get(i + 1)).getValue()) {
                result.append(" - ");
                result.append(day);
            }
        } else {
            result.append(", ");
            result.append(day);
        }
        previousIndex = DayEnum.valueOf(day).getValue();
    }
    return result.toString();
}

Check out the answer here: http://stackoverflow.com/questions/1978933/a-quick-and-easy-way-to-join-array-elements-with-a-separator-the-opposite-of-sp Hope this helps. — Anthony, Dec 03 '14 at 20:47
If that list will always be unique, why not create your own simple implementation? — austin wernli, Dec 03 '14 at 20:48

kamoor · Accepted Answer · 2014-12-04T03:58:45.133

You can try something like this.

enum DAY {
MONDAY(1), 
TUESDAY(2), 
WEDNESDAY(3),
THURSDAY(4),
FRIDAY(5),
SATURDAY(6),
SUNDAY(7);

private int value;

DAY(int x) {
    this.value = x;
}

public int getValue() {
    return value;
}}

Then use following method to convert.

public static String concateDays(List<String> days) {

    StringBuffer result = new StringBuffer(days.get(0));
    int previousIndex = DAY.valueOf(days.get(0)).getValue();
    int length = days.size();

    for (int i=1; i< days.size(); i++) {
        String day = days.get(i);
        if(previousIndex + 1 == DAY.valueOf(day).getValue()){
            if(i == length -1 || DAY.valueOf(day).getValue() + 1 != DAY.valueOf(days.get(i+1)).getValue()){
                result.append(" - ");
                result.append(day);
            }
        }else{
            result.append(", ");
            result.append(day);
        }
        previousIndex = DAY.valueOf(day).getValue();
    }
    return result.toString();
}

Thank you! Your code worked with a few edits, which I've provided in my edited question w/ the solution. — FilmiHero, Dec 03 '14 at 22:15

Convert day of week list to hyphenated String

SOLUTION

1 Answers1