Java – How to append a newline character for all lines except the last one


I'm iterating through a HashMap (see my earlier question for more detail) and building a string consisting of the data contained in the Map. For each item, I will have a new line, but for the very last item, I don't want the new line. How can I achieve this? I was thinking I could so some kind of check to see if the entry is the last one or not, but I'm not sure how to actually do that.


Best Solution

Change your thought process from "append a line break all but the last time" to "prepend a line break all but the first time":

boolean first = true;
StringBuilder builder = new StringBuilder();

for (Map.Entry<MyClass.Key,String> entry : data.entrySet()) {
    if (first) {
        first = false;
    } else {
        builder.append("\n"); // Or whatever break you want
           .append(": ")