converting elements of a list to string

Question

I would like to obtain the string text of the elements stored in a list, say List<Car>. Would the toArray() and the toString() methods be the best options?

Answer 1

Yes, but doing it manually gives you more control:

// initialize with the exact length
List<String> stringsList = new ArrayList<String>(listOfCard.size()); 
for (Car car : listOfCars) {
    stringsList.add(car.toString());   
}

If you haven't overridden the toString() method and don't want to override id, you can use car.getName() isntead of car.toString() (or any property combination you like)

Answer 2

for (Car car : carsList) {  // carsList is the object of List<Car>
    System.out.println(car);
}

Note: The above will display the meaningful message only when you have overridden the toString() method of Car class.

e.g

public class Car {

    private String carName;

    ....
    ....

    public String toString() {
        return carName;
    }
}

The toString() method should be overridden to return meaningful information about the object in the string form.

In your case, I think the meaningful info would be all the details of the car. So overriding toString() method is best approach instead of using getCarName() or similar methods.

Answer 3

There is a static toString(Object[]) method an java.util.Arrays. Calling it with the toArray() result of the List (as you suggested) should do the job.

Answer 4

Providing you don't object to the string output following the convention:

[A, B, C]

... you can simply call the List'stoString() method to obtain your output (I'm not sure why people are advocating using a loop for this). It may also be sensible to override Car's toString() method to return a human-friendly description of the object.

However, if you wish to obtain each element as an individual String you will need to iterate over the List one element at a time.

Answer 5

Another idea is to use the Apache Commons Lang to write the following code:

StringUtils.join(myList);

The interest is that you also can provide a separator, for example:

StringUtils.join(myList, " ; ");