Quick Tip – How to convert a Java List to a Java String

#java #todayilearned

Hello ! I’m Xavier Jouvenot and in this small post, I am going to explain how to convert a Java List<Integer> to a Java String.

Self promotion: You can find other articles on Android development on my website 😉

Solution

For the people who only want the solution, to quickly copy-paste it in there code, here it is 😉

List<Integer> my_list;
// some code to fill the list ...

StringBuilder sb = new StringBuilder();
for (int i = 0; i < my_list.size(); ++i)
{
    sb.append(my_list.get(i));
    if(i != my_list.size() - 1)
    {
        sb.append(", ");
    }
}
String s = sb.toString();

Explanation

If you read this, it may be that you want to understand how the previous solution achieve the goal of transforming the List<Integer> into a String, and this is what I am going to try to explain. 🙂

First of all, we create the list and fill it with whatever integer you want. And we create a StringBuilder which is going to help us doing the transformation.

Then, we transfer the information from the List to the StringBuilder and format it how we want to. In our case, we are separating the each numbers of the list with a comma and a space.

Finally, we create a String with all the information we want, by using the method toString of StringBuilder.

Thank you all for reading this article,And until my next article, have a splendid day 😉